Instructional Video
Loyola University Chicago

Math Flix: Similar Figures: Proof Using Proportions

For Students 9th - 10th Standards
This QuickTime movie provides an opportunity to develop the basic geometric term, similar, by checking to see if figures are proportionaly similar. As you watch and listen to the teacher and student interact it helps clarify the thinking...
Instructional Video
Sophia Learning

Sophia: Pythagorean Theorem Proof

For Students 9th - 10th Standards
Find the area of several figures to prove the Pythagorean theorem. Complete quiz to check understanding. [5:16]
Instructional Video
Study Pug

Study Pug: Perpendicular Line Proofs

For Students 9th - 10th Standards
Video lesson explains angles, lines, and transversals. [9:33]
Instructional Video
Sophia Learning

Sophia: Pythagorean Theorem Proof

For Students 9th - 10th Standards
Prove the Pythagorean theorem and take a quiz to assess learning.
Instructional Video
Khan Academy

Khan Academy: Geometry: Part 1 of Proof of Heron's Formula

For Students 9th - 10th Standards
Demonstrates how to derive a version of Heron's formula using the Pythagorean Theorem and the formula for the area of a triangle. Applies Heron's formula to solve a sample problem. [10:59]
Instructional Video
Khan Academy

Khan Academy: Geometry: Proof: Opposite Angles of Parallelogram Congruent

For Students 9th - 10th Standards
This video tutorial demonstrates how to prove that the opposite angles of a parallelogram are congruent based on knowledge of the special angles created when parallel lines are cut by a transversal. [4:08]
Instructional Video
Khan Academy

Khan Academy: Geometry: Proof: Diagonals of Parallelogram Bisect Each Other

For Students 9th - 10th Standards
Demonstrates how to prove that the diagonals of a parallelogram bisect each other based on knowledge of the special angles created when parallel lines are cut by a transversal and the triangle congruency postulates. [9:06]
Instructional Video
Khan Academy

Khan Academy: Geometry: Proof: Opposite Sides of Parallelogram Congruent

For Students 9th - 10th Standards
Demonstrates how to prove that the opposite sides of a parallelogram are congruent based on knowledge of the special angles created when parallel lines are cut by a transversal and the triangle congruency postulates. [8:30]
Instructional Video
Khan Academy

Khan Academy: Geometry: Angles of Parallel Lines 2

For Students 9th - 10th Standards
Explains how to determine the measures of all the angles formed when parallel lines are cut by a transversal based on the measure of one angle. Explains how to use corresponding congruent angles to determine if lines cut by a transversal...
Instructional Video
Khan Academy

Khan Academy: Proof: All Circles Are Similar

For Students 9th - 10th Standards
Demonstrates how to use a unit circle on a coordinate grid to prove that all circles are similar. [1:34]
Instructional Video
Sophia Learning

Sophia: Cpctc: Lesson 1

For Students 9th - 10th
This lesson [8:19] will demonstrate the use of CPCTC in triangle congruency proofs. It is 1 of 4 in the series titled "CPCTC."
Instructional Video
Sophia Learning

Sophia: Cpctc: Lesson 4

For Students 9th - 10th
This video lesson [6:45] will demonstrate the use of CPCTC in triangle congruencey proofs. It is 4 of 4 in the series titled "CPCTC."
Instructional Video
Sophia Learning

Sophia: Cpctc (Corresponding Parts of Congruent Triangles)

For Students 9th - 10th Standards
Complete a multiple step proof to determine if two triangles are congruent. Take quiz to check for understanding.
Instructional Video
Sophia Learning

Sophia: Counterexamples: Lesson 4

For Students 9th - 10th
This lesson will help a learner understand counterexamples. It is 4 of 7 in the series titled "Counterexamples." [3:05]
Instructional Video
Khan Academy

Khan Academy: Perpendicular Radius Bisects Chord

For Students 9th - 10th Standards
Proof that if a radius is perpendicular to a chord then it bisects the chord. This video also appears in the Geometry: Circles strand. [6:57]
Instructional Video
Khan Academy

Khan Academy: Linear Algebra: Vector Triangle Inequality

For Students 9th - 10th
Video first reviews the Cauchy-Schwarz inequality. Then shows a proof of the triangle inequality for vectors and relates it to the triangle inequality from 2-dimensional geometry. [18:53]
Instructional Video
Virtual Nerd

Virtual Nerd: What Is a Theorem?

For Students 9th - 10th
A theorem is a general mathematical statement that can be used to help solve all sorts of problems. Watch this tutorial for an introduction to theorems. [4:11]
Instructional Video
Virtual Nerd

Virtual Nerd: What Is Inductive Reasoning?

For Students 9th - 10th
Inductive reasoning is observing data and patterns to make predictions. Watch this tutorial to learn about inductive reasoning. [3:48]
Instructional Video
Khan Academy

Khan Academy: Linear Algebra: Vector Triangle Inequality

For Students 9th - 10th
Video first reviews the Cauchy-Schwarz Inequality the shows a proof of the Vector Triangle Inequality and relates it to the Triangle Inequality from 2-dimensional Geometry. [18:53]
Instructional Video
Khan Academy

Khan Academy: Vector Dot and Cross Products: Vector Triangle Inequality

For Students 9th - 10th
Thi videoreviews the Cauchy-Schwarz inequality and then shows a proof of the triangle inequality for vectors and relates it to the triangle inequality from 2-dimensional geometry.
Instructional Video
Loyola University Chicago

Math Flix: Pythagorean Theorem Puzzle

For Students 5th - 8th
This QuickTime movie uses a tangram-like puzzle to help understand the Pythagorean Theorem. As you watch and listen to the teacher and student interact it helps clarify the thinking behind applying this concept.
Instructional Video
Sophia Learning

Sophia: Counterexamples: Lesson 6

For Students 9th - 10th
This lesson will help a learner understand counterexamples. It is 6 of 7 in the series titled "Counterexamples." [1:54]
Instructional Video
Virtual Nerd

Virtual Nerd: What Is a Biconditional Statement?

For Students 9th - 10th
When a conditional statement and its converse are both true, you can write them as one statement called a biconditional statement. This tutorial illustrates this special kind of statement. [6:27]

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