Khan Academy
Khan Academy: Triangles: Fill in the Blank Triangle Proofs Example 1
In this video, we listen to how a geometry exercise is completed as the presenter demonstrates the reasoning behind proving that the corresponding parts of triangles are congruent. [9:42]
Khan Academy
Khan Academy: Triangles: Fill in the Blank Triangle Proofs Example 2
This video will fill in the blanks in a proof showing that the triangles are congruent.
Khan Academy
Khan Academy: Two Column Proof Showing Segments Are Perpendicular
Using triangle congruency postulates to show that two intersecting segments are perpendicular
Khan Academy
Khan Academy: Sss to Show a Radius Is Perpendicular to a Chord That It Bisects
More on the difference between a theorem and axiom. Proving a cool result using SSS.
Khan Academy
Khan Academy: Worked Examples: Geometry: Ca Geometry: Proof by Contradiction
Students explore how to do a geometric proof by contradiction.
Khan Academy
Khan Academy: Triangles: Bhaskara's Proof of Pythagorean Theorem
An elegant visual proof of the Pythagorean Theorem developed by the 12th century Indian mathematician Bhaskara.
Khan Academy
Khan Academy: Triangles: Another Pythagorean Theorem Proof
Students explore the Pythagorean Theorem by exploring a visual proof of the Theorem as they watch a video tutorial.
Sophia Learning
Sophia: Intermediate Proof
Use the two-column proof and the flow proof to prove two triangles congruent.
Sophia Learning
Sophia: Types of Proofs
Explore the similarities and differences between paragraph proofs, flow chart proofs, and two-column proofs. Assess learning with a quiz.
Khan Academy
Khan Academy: Triangles: Wrong Statements in Proofs Example 1
A video analyzing how to recognize wrong statements in a proof. [2:48]
Khan Academy
Khan Academy: Triangles: Proof: Triangle Altitudes Are Concurrent (Orthocenter)
Demostrates how to take any triangle and make it become the medial triangle of a larger triangle. Also explains that the three altitudes of a triangle are concurrent. [10:01]
Khan Academy
Khan Academy: Geometry: Part 1 of Proof of Heron's Formula
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]
Khan Academy
Khan Academy: Geometry: Deductive Reasoning
This video explains what is deductive reasoning.
Khan Academy
Khan Academy: Geometry: Part 2 of the Proof of Heron's Formula
Completes the proof of Heron's formula that was begun in the video, "Part 1 of Proof of Heron's Formula." [12:08]
Khan Academy
Khan Academy: Triangles: Congruent Triangle Proof Example
Students learn how to prove that two triangles are congruent using midpoint of line segments.
Khan Academy
Khan Academy: Geometry: Euler's Line Proof
Proves that the circumcenter, orthocenter, and centroid all lie on the same line, the Euler line. Proof relies on understanding of properties of similar triangles and properties of special parts of a triangle. [9:50]
Khan Academy
Khan Academy: Basic Triangle Proofs Module Example 2
A video proving that the given triangles are congruent by ASA.
