# High School Mathematics: Geometry

## Video Lectures

Displaying all 86 video lectures.

Lecture 1Play Video |
Points Lines & Planes in GeometryI introduce Points, Lines, and Planes along with many definitions like collinear and coplanar points to begin our studies of Geometry. Parts D and E of the last example should read is there a plane in the solid that contains these 3 vertices, not if they are coplanar. Asking if they are coplanar is the same type of error I corrected early in the video. Three points define a plane. EXAMPLES at 16:35 Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 2Play Video |
More Postulates & Theorems Points, Lines, & PlanesI introduce 5 more postulates relating to points, lines, and planes. These postulates are then used to prove the first three theorems in Geometry. Theorem 1, If 2 lines intersect, then they intersect in exactly one point. Theorem 2, Through a line and a point not in the line there is exactly one plane. Theorem 3, If 2 lines intersect, then exactly 1 plane contains the lines. EXAMPLES at 5:41 12:35 19:50 Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 3Play Video |
Segment, Ray, Distance on a Number LineI introduce the basic geometric figures of segments, rays, and distance on a number line. This lecture includes discussions about the Ruler Postulate, Segment Addition Postulate, Congruency is defined, Midpoint of a Segment, and finally Bisector of a Segment. |

Lecture 4Play Video |
Introduction to AnglesI introduce the basic structure of angles in Geometry, how to name them based on points, and size such as acute and obtuse. I also introduce the Protractor Postulate, Angle addition Postulate, define congruent angles, angle bisector, and adjacent angles. EXAMPLES at 12:20 18:30 22:58 |

Lecture 5Play Video |
Special Angle PairsEXAMPLES start at 9:27 I introduce Adjacent Angles, Vertical Angles, Supplementary Angles, Linear Pair, and Complementary Angles in Geometry. |

Lecture 6Play Video |
Basic Constructions Segment & AngleI show you how to construct a congruent segment and a congruent angle using just a straight edge and a compass. |

Lecture 7Play Video |
Angle and Segment Bisector ConstructionsI give you the steps and demonstrations on how to construct a perpendicular bisector of a segment and an angle bisector with a compass and a straight edge. |

Lecture 8Play Video |
Distance Formula & Pythagorean TheoremI introduce the distance formula and show it's relationship to the Pythagorean Theorem. This video includes three examples of finding the distance between two points. EXAMPLES at 2:54 14:21 17:41 |

Lecture 9Play Video |
Midpoint FormulaI introduce the midpoint formula and work thought three examples to your understanding. The first two examples are finding a midpoint, the second involves fractions. The last example shows you how to find an unknown endpoint when you know the midpoint and one endpoint of the segment. EXAMPLES at 2:21 9:22 15:00 |

Lecture 10Play Video |
Perimeter of a Plane RegionI introduce finding the perimeter of a 2 dimensional plane region and work through 6 examples to help your studies. EXAMPLES at 5:52 7:05 14:38 15:22 22:37 26:07 |

Lecture 11Play Video |
Area of a Plane RegionI work through multiple examples of finding the area of 2 dimentional plane areas. EXAMPLES at 6:10 10:55 12:28 15:58 19:59 |

Lecture 12Play Video |
Deductive Reasoning If Then StatementsI introduce deductive reasoning by introducing the structure of "if, then" statements. I explain conditional statements, converse statements, bi-conditional statements, inverse statements, and finally contrapositive statements. |

Lecture 13Play Video |
Intro to 2 Column Geometry ProofsI introduce the structure of 2 column proofs and then remind you of the Properties of Equality you learned in Algebra. I finish by working through three examples. EXAMPLES at 13:10 17:09 23:43 Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 14Play Video |
Congruent AnglesI introduce geometry theorems that involve congruent angles such as vertical angles. I work through a couple of examples and do a 2 column proof of the Vertical Angle Theorem. EXAMPLES at 2:08 6:54 10:40 |

Lecture 15Play Video |
Parallel Lines & Skew Lines, Angles formed by a TransversalI define and show you how to identify Skew and Parallel lines in a drawing. I then discuss the types of angles you have when 2 or more lines are cut by a transversal. |

Lecture 16Play Video |
Parallel Lines & Transversal AnglesI introduce the properties of angles that are formed when 2 parallel lines are intersected by a transversal. These angles include Corresponding, Alternate Interior, Alternate Exterior, and Same-Side Interior angles. I finish with 5 examples, the last of which is a proof involving parallel lines. EXAMPLES at 2:00 6:06 11:13 14:10 |

Lecture 17Play Video |
Proving Lines ParallelWe take another look at parallel lines being cut by a transversal. I work through two examples where we are proving the lines that were cut by a transversal are parallel. EXAMPLES at 4:51 13:04 |

Lecture 18Play Video |
Parallel & Perpendicular Lines ProofI introduce 2 more theorems that can verify that 2 lines are parallel. Each of these two theorems are proven with 2 column proofs. EXAMPLES at 0:04 7:54 |

Lecture 19Play Video |
Angles of Triangles and Parallel LinesI introduce the theorem that state the interior sum of the angles of a triangle add up to 180 degrees and show how this is true with parallel lines. The second theorem I cover explains how an exterior angle of a triangle is equal to the sum of the 2 interior remote angles. EXAMPLES at 6:34 9:00 14:46 19:43 23:32 |

Lecture 20Play Video |
Graphing Lines in Slope-Intercept form y=mx+bI introduce how to graph a line in slope intercept form. I also discuss graphing vertical and horizontal lines. Please check out my other lessons about Linear Functions: Graphing Lines with x-Intercepts and y-Intercepts https://www.youtube.com/watch?v=KtgddI4qIok Slope and Equations of Lines https://www.youtube.com/watch?v=xf8-BEdoSss Equations of Lines and Graphing https://www.youtube.com/watch?v=Wmi1EysOHUQ Equations of parallel and perpendicular lines https://www.youtube.com/watch?v=ECljEiIgX_M Linear Functions, their Attributes, & Interpreting Slope and y-Intercept https://www.youtube.com/watch?v=qbNTy0oMq1c Check out www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 21Play Video |
Equations of Lines and GraphingContinued discussion about equations of lines and the three equation forms. Graphing of linear functions also included. Please check out my other lessons about Linear Functions: Graphing Lines in Slope-Intercept form y=mx+b https://www.youtube.com/watch?v=xyVJZKu7Euw Graphing lines using X & Y Intercepts https://www.youtube.com/watch?v=KtgddI4qIok Slope and Equations of Lines https://www.youtube.com/watch?v=xf8-BEdoSss Equations of parallel and perpendicular lines https://www.youtube.com/watch?v=ECljEiIgX_M Regression Lines and Correlation with TI-84 https://www.youtube.com/watch?v=L_h7nqNqgPs Linear Functions, their Attributes, & Interpreting Slope and y-Intercept https://www.youtube.com/watch?v=qbNTy0oMq1c Check out www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 22Play Video |
Rate of Change Slope & Point Slope Equation of LinesIntroduction to finding slope and graphing lines. Please check out my other lessons about Linear Functions: Graphing Lines in Slope-Intercept form y=mx+b https://www.youtube.com/watch?v=xyVJZKu7Euw Graphing lines using X & Y Intercepts https://www.youtube.com/watch?v=KtgddI4qIok Equations of Lines and Graphing https://www.youtube.com/watch?v=Wmi1EysOHUQ Equations of parallel and perpendicular lines https://www.youtube.com/watch?v=ECljEiIgX_M Regression Lines and Correlation with TI-84 https://www.youtube.com/watch?v=L_h7nqNqgPs Linear Functions, their Attributes, & Interpreting Slope and y-Intercept https://www.youtube.com/watch?v=qbNTy0oMq1c Check out www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 23Play Video |
Equations of Parallel and Perpendicular LinesAn introduction to finding the equations of lines that pass through a point and are parallel or perpendicular to a given line. Please check out my other lessons about Linear Functions: Graphing Lines in Slope-Intercept form y=mx+b https://www.youtube.com/watch?v=xyVJZKu7Euw Graphing lines using X & Y Intercepts https://www.youtube.com/watch?v=KtgddI4qIok Slope and Equations of Lines https://www.youtube.com/watch?v=xf8-BEdoSss Equations of Lines and Graphing https://www.youtube.com/watch?v=Wmi1EysOHUQ Regression Lines and Correlation with TI-84 https://www.youtube.com/watch?v=L_h7nqNqgPs Linear Functions, their Attributes, & Interpreting Slope and y-Intercept https://www.youtube.com/watch?v=qbNTy0oMq1c Check out www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 24Play Video |
Congruent Polygons & Third Angle TheoremI define congruent polygons and prove the Third Angle Theorem. EXAMPLES AT 4:28 10:40 16:24 22:25 |

Lecture 25Play Video |
Congruent Triangles SSS SASI introduce the Side-Side-Side Postulate and Side-Angle-Side Postulate and work through 4 2 column proofs showing you how these can prove 2 triangles are congruent. EXAMPLES AT 0:55 6:04 11:39 14:42 16:43 Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 26Play Video |
Congruent Triangles ASA AASI introduce the ASA Postulate and the AAS Theorem for proving two triangles are congruent and work through 4 examples of including 2 column proofs. EXAMPLES AT 0:50 7:19 9:45 13:38 |

Lecture 27Play Video |
Non Congruence Theorems AAA SSANow that we know 4 ways to prove two triangles are congruent, lets look at two non-congruence theorems. Students often use these to prove triangles are congruent which is incorrect. |

Lecture 28Play Video |
CPCTC Corresponding Parts of Congruent Triangles are CongruentI introduce "Congruent Parts of Congruent Triangles are Congruent" and work through two proofs that used this concept. EXAMPLES AT 0:10 4:26 |

Lecture 29Play Video |
Isosceles & Equilateral Triangle PropertiesI introduce 2 theorems about the properties of Isosceles and Equilateral Triangles. These theorems discuss how the base angles are congruent and that the bisector of the vertex is also a perpendicular bisector of the base. This video includes 2 proofs and 2 algebraic examples. EXAMPLES AT 0:05 9:06 15:37 22:45 |

Lecture 30Play Video |
Equilateral Triangle / Equiangular TriangleI introduce and define equilateral triangles and equiangular triangles. I then work through 3 examples involving the lengths of sides and angles. EXAMPLES AT 2:55 8:14 15:52 |

Lecture 31Play Video |
Congruent Right Triangles HL Hypotenuse Leg TheoremI introduce the Hypotenuse Leg Theorem or HL and prove it in a 2 column proof. I also work through three examples using this theorem.EXAMPLES AT 11:10 13:00 14:20 Second Version of Proof at 21:03 |

Lecture 32Play Video |
Triangle Midsegment TheoremI introduce and work through many examples involving the Triangle Midsegment Theorem. When a segment connects the midpoints of two sides of a triangle, that midsegment is half the length of the third side and also parallel to that third side. EXAMPLES AT 1:05 10:42 13:55 |

Lecture 33Play Video |
Proving Midsegment TheoremUsing the midpoint, slope, and distance formulas I prove the Midsegment Theorem which states a segment that connect the midpoints of 2 sides of a triangle is parallel and half the length of the third side. |

Lecture 34Play Video |
Perpendicular Bisector TheoremI introduce the Perpendicular Bisector Theorem and the Converse Theorem and prove both. I finish by working through three examples. EXAMPLES AT 0:34 11:55 14:38 20:15 |

Lecture 35Play Video |
Angle Bisector TheoremI introduce the Angle Bisector Theorem and prove it, introduce the Converse of the Angle Bisector Theorem, and finish by working through two examples. EXAMPLES AT 0:20 9:40 15:19 |

Lecture 36Play Video |
Triangle Perpendicular Bisectors & CircumcenterI introduce the Perpendicular Bisector Theorem in triangles. We discuss how the point of concurrency is the center of the circumcenter. The circumcenter is the center of the circle that circumscribed the triangle. I finish by working through two examples of finding the circumcenter of a triangle given its three vertices. EXAMPLES AT 3:56 9:36 13:47 |

Lecture 37Play Video |
Triangle Angle Bisectors & IncenterI introduce Concurrency of Angle Bisectors in Triangles and discuss how they meet at the center of the inscribed circle. EXAMPLES AT 2:23 6:28 |

Lecture 38Play Video |
Medians of Triangles & CentroidI introduce Medians in Triangles and their point of concurrency...the centroid. I finish by working through three example dealing with the centroid and the ratio of the median segments. EXAMPLES AT 5:43 7:47 12:48 |

Lecture 39Play Video |
Altitudes of Triangles and OrthocenterI introduce altitudes in triangles and point of concurrency, the orthocenter. I finish by working through two examples, the last of which finding the orthocenter given the three vertices of a triangle. EXAMPLES AT 7:10 10:31 |

Lecture 40Play Video |
Triangle Inequality TheoremI introduce Inequalities in 1 Triangle in which we look at how the lengths of the sides are related to the size of the angles that are opposite those sides. EXAMPLES AT 2:34 6:04 9:55 11:43 14:25 15:30 At minute 2:07 I misspoke, 20+30 is 50 of course:D |

Lecture 41Play Video |
Hinge Theorem Inequalities 2 TrianglesI introduce the Hinge Theorem which allows us to look at the size relationship between the angles and sides within multiple triangles. I work through many examples in this video. EXAMPLES AT 1:40 2:28 3:30 4:48 5:32 8:52 |

Lecture 42Play Video |
Polygon Angle Sum TheoremsI introduce Polygon Angle Sum Theorems, not Polynomial Angle Sum Theorem which isn't even a theorem! This includes finding the Sum of the Interior Angles of a Polygon and the Sum of the Exterior Angles. I also talk about finding the individual interior and exterior angles of Regular Polygons...after I define what a Regular Polygon is:) EXAMPLES AT 3:30 4:29 5:38 7:00 10:40 14:18 15:22 17:26 I do not know why I wrote Polynomial Angle Sum Theorem???!!! Too many hours working between teaching and YouTube I guess. |

Lecture 43Play Video |
Properties of ParallelogramsI introduce the Properties of Parallelograms...the opposite sides are equal, the opposite angles are equal, the consecutive angles are supplementary, and the diagonals bisect each other. I work through four algebraic examples in this video at 4:28 14:30 |

Lecture 44Play Video |
Proving Quadrilaterals are ParallelogramsWe work with the converse of the theorems we learned in the last video to prove, or make sure, that quadrilaterals are parallelogram. I work through two algebraic examples and one two column proof. EXAMPLES AT 2:33 8:43 12:22 |

Lecture 45Play Video |
Rhombuses, Rectangles, and SquaresI introduce the properties of Rhombuses, Rectangles, and Squares and finish by working through five examples to help you through your homework. Rhombus examples 5:39 Rectangle examples 14:05 |

Lecture 46Play Video |
More Examples Rhombus & RectangleI continue my examples with Rhombuses, Rectangles, and Squares. These two algebraic examples require slightly more advanced algebra techniques and a need to check your answers with the original Geometric shape. EXAMPLES AT 0:05 12:01 |

Lecture 47Play Video |
Properties of Trapezoids & Mid Segment TheoremI introduce Properties of Trapezoids and the Mid-segment Theorem EXAMPLES AT 3:56 7:54 13:20 |

Lecture 48Play Video |
Properties of KitesI introduce many properties of Kites, work through three examples of finding missing angles, and finish with a quick two column proof. EXAMPLES 5:55 10:09 12:54 14:46 |

Lecture 49Play Video |
Polygons in Coordinate PlaneI work through four examples of classifying type of polygons in the coordinate plane using the distance, slope, and midpoint formulas. EXAMPLES AT 2:22 10:24 15:29 23:13 |

Lecture 50Play Video |
Ratios & ProportionsI introduce how to set up Ratios and Proportions and then work through a number of examples. EXAMPLES start at 1:34 and 6:28 and 14:44 and 23:29 Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 51Play Video |
Proportions and Similar Polygons / Similar FiguresI work through 5 examples of solving for missing sides of similar polygons. Similar polygons have linear sides, the corresponding angles are congruent, and the corresponding sides are proportional. The equal proportions, or constant ratios of the side lengths, are called the Scale Factor. EXAMPLES at 3:15 6:46 12:17 15:21 17:34 22:24 |

Lecture 52Play Video |
Proving Triangles are Similar AA SAS SSSI introduce the AA Postulate and the SAS & SSS to show you how to prove two triangles are similar. This video includes about 5 examples. The last word in the definition of SAS for similar triangles should be similar, not congruent. Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 53Play Video |
Similarity in Right TrianglesWhen you drop an altitude from the right angle of a right triangle you get three triangles that are all similar to each other. I explain this and finish by working through three examples in this video. EXAMPLES at 5:26 9:33 17:06 23:15 28:08 |

Lecture 54Play Video |
Side Splitter Theorem Proportions in TrianglesI introduce the Side Splitter Theorem for triangles and its corollary that applies to parallel lines intsecting multiple transversals. I work through two algebra examples involving proportions. EXAMPLES at 1:34 6:23 |

Lecture 55Play Video |
Proportions in Triangles Angle BisectorI introduce the Triangle Angle Bisector Theorem and work through 2 examples to help you set up and solve equal proportions. Examples at 2:40 8:23 |

Lecture 56Play Video |
Pythagorean TheoremI explain how the Pythagorean Theorem allows you to find the length of an unknown side of a right triangle. |

Lecture 57Play Video |
Converse Pythagorean Theorem & TriplesI explain the Converse Pythagorean Theorem and what Pythagorean Triples are. |

Lecture 58Play Video |
Special Right Triangles 45-45-90 30-60-90I introduce and work through 6 examples of problems involving 30 60 90 triangles and 45 45 90 triangles. All work is done in exact form and not rounded off decimals from a calculator. EXAMPLES at 3:30 4:47 10:05 11:46 14:05 19:03 Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 59Play Video |
Right Triangle Trigonometry Part 1: Finding Missing SidesI introduce evaluating trigonometric functions about a right triangle. We will set up the trig ratios given a right triangle, and find missing angle measures, and sides of right triangles using the pythagorean theorm and the trig functions. Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 60Play Video |
Right Triangle Trigonometry Part 2: Solving for Acute AnglesLink to Part 1 https://www.youtube.com/watch?v=pkjuVZUdcvo I introduce evaluating trigonometric functions about a right triangle. We will set up the trig ratios given a right triangle, and find missing angle measures, and sides of right triangles using the pythagorean theorm and the trig functions. Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 61Play Video |
Angle of Elevation and Depression Right Triangle TrigI do some more examples or right triangle trigonometry on Geometry application problems that involve Angle of Depression and/or Elevation. EXAMPLES at 1:58 8:36 13:06 18:57 Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 62Play Video |
Area Parallelograms and TrianglesI introduce the formulas to find the area of Parallelograms and Triangles. I then work through 6 examples of increasing levels of difficulty. EXAMPLES at 5:50 8:27 9:45 16:38 20:32 25:42 |

Lecture 63Play Video |
Area Trapezoid Rhombus KiteI work through 6 examples of finding area of Trapezoids, Rhombuses, and Kites. EXAMPLES at 3:00 8:30 13:37 15:29 20:08 25:24 |

Lecture 64Play Video |
Area of Regular Polygon Introduction with Hexagon ExamplesI introduce how to find the area of a regular polygon and finish by working through two examples involving hexagons. The second example is more difficult than the first. |

Lecture 65Play Video |
Area Regular Polygons with TrigonometryI work through two more examples involving the area of Regular Polygons. These examples require the use of Right Triangle Trigonometry, or Sin Cos Tan, to complete. |

Lecture 66Play Video |
Perimeter and Area Ratios of Similar FiguresI discuss the relationship between the perimeter and area of similar objects. As an example, I show how increasing the perimeter by a scaler multiple of 3 increases the area by 3^2 or nine. |

Lecture 67Play Video |
Circle Intro and Arc LengthI introduce many basic definitions that are related to circles and also the area and circumference formula. I then work through many examples examples of naming minor and major arcs, central angles, and finding arc lengths. EXAMPLES at 9:55 19:50 21:10 25:38 |

Lecture 68Play Video |
Sector and Segment Area in CirclesI work through four examples of finding Sector Area and Segment Area of circles. EXAMPLES at 2:03 6:16 15:23 23:34 |

Lecture 69Play Video |
Segment Area in Circles Quicker MethodsUsing alternative area formulas for triangles like Heron's Formula and the Area of an Oblique Triangle formula I work through two examples of finding the area of a segment in a circle. EXAMPLES at 3:30 7:49 |

Lecture 70Play Video |
Geometric Probabilities LengthI introduce Geometric Probabilities and work through two examples that involve length. EXAMPLES AT 2:13 6:57 I do some mental math and say that 3/10 is .3333, it is .3 of course. |

Lecture 71Play Video |
Geometric Probabilities AreaI work through three examples of finding Geometric Probabilities that involve areas of triangles, circles, and a regular polygon:) EXAMPLES AT 1:25 5:33 10:49 |

Lecture 72Play Video |
Surface Area of a Right PrismI introduce Right and Oblique Prisms and then work through two examples of finding the Lateral Area and Surface Areas of Right Prisms at 7:07 13:52 |

Lecture 73Play Video |
Surface Area Of a CylinderI introduce finding the Lateral and Surface Area of Right Cylinders. I finish by working through three examples at 2:54 6:15 13:30 |

Lecture 74Play Video |
Surface Area of a Regular Pyramid Non-Trig ExamplesI introduce finding Surface Area of a Pyramid, vocabulary, and work through three examples to help your understanding and complete your homework. No Trigonometry is required for these examples at 4:41 9:49 21:30 |

Lecture 75Play Video |
Surface Area of a Pyramid with TrigonometryI work through two examples of finding the surface area of right regular pyramids at 0:51 9:01 |

Lecture 76Play Video |
Surface Area of a ConeI introduce how to find the Surface Area of a Right Cone and finish by working through three examples at 2:29 6:27 10:39 |

Lecture 77Play Video |
Volume of a Prism & Volume of a CylinderI introduce how to find the Volume of a Prism or Cylinder. I then work through 5 examples in increasing difficulty to help you understand this concept. EXAPMLES at 1:45 4:44 12:53 15:34 17:58 In my last example I keep saying I am working with a bolt, but that would actually be a nut! |

Lecture 78Play Video |
Volume of a Pyramid 3 ExamplesI work through three examples of finding the volume of pyramids. Examples at 1:44 7:09 10:43 |

Lecture 79Play Video |
Volume of a Cone 3 ExamplesI introduce finding volumes of cones and then work through 3 examples at 2:16 8:42 13:59 |

Lecture 80Play Video |
Surface Area of a Sphere & Volume of a SphereI introduce how to find the Surface Area & Volume of Sphere and work through 4 examples at 2:53 5:51 11:25 18:47 Sorry for the mistake, I misspelled hemisphere. |

Lecture 81Play Video |
Tangent Lines to CirclesI introduce tangent lines and work through 6 examples to help explain how they relate to circles. Examples at 6:00 7:41 10:18 15:56 18:43 12:31 Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 82Play Video |
Given a Tangent Line & Circle Find the Point of TangencyIn this lesson I start by setting up the example with you. Then at 15:08 I show you how to find the Point of Tangency when given the equation of the tangent line and a circle. In the first solution I work through the slope formula using the fact that the tangent line and radius are perpendicular. The second method starting at 26:00 I just use straight substitution to solve the system of equations between the tangent line and the circle. Check out www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 83Play Video |
Chords Arcs and Diameters in CircleI introduce the concept of Chords in a circle and then give you 7 theorems that explain the relationships of chords, arcs, diameters, and central angles is circles. |

Lecture 84Play Video |
Inscribed Angles in Circles and Tangent LinesI define Inscribed Angles, Inscribed Angles involving Tangent Lines, and 3 Corollaries of Inscribed Angles. I work through five examples to help your understanding. |

Lecture 85Play Video |
Angles in Circles Chords Secants Tangents and ArcsI introduce how to find angle measures and arc measures in circles created by Secants, Chords, and Tangents that intersect inside or outside of a circle. I work through three multiple part examples to help you in your understanding of how to work these problems. Check out http://www.ProfRobBob.com, there you will find my lessons organized by class/subject and then by topics within each class. |

Lecture 86Play Video |
Segment Lengths in Circles with Chords, Secants, and TangentsI introduce how to find segment lengths in circles that are created by the intersection of Chords, Secants, and Tangent lines. I finish by working through 3 examples to help your understanding. |