Instructional Video7:19
Cerebellum

Geometry - Triangle Proofs

9th - 12th
Understand and making sense of geometry: Proofs. This is part 2 from the series 'Geometry Program'.
Instructional Video
Khan Academy

Khan Academy: Geometry:sss to Show a Radius Is Perpendicular to Chord It Bisects

9th - 10th Standards
Explains how to prove that a radius is perpendicular to a chord that it bisects by using the side-side-side triangle congruence postulate. [8:19]
Instructional Video
Khan Academy

Khan Academy: Geometry: Ca Geometry: Proof by Contradiction

9th - 10th Standards
Demonstrates solutions to problems #4-6 of California Geometry released state test questions. Problems address understanding of proof by contradiction and proving triangles congruent. [11:56]
Instructional Video
Khan Academy

Khan Academy: Geometry: Congruent Parts of Iscosceles Triangles

9th - 10th Standards
Proof that if the legs of an isosceles triangle are congruent then the base angles are congruent and vice versa using triangle congruency postulates. The proof is written as a two-column proof. [9:03]
Instructional Video
Khan Academy

Khan Academy: Geometry: Congruent Triangles and Sss

9th - 10th Standards
In this video tutorial [11:29], the instructor explains how to use triangle congruence to identify measures of corresponding sides and angles in triangles. Defines side-side-side (SSS) postulate. Practice problems available.
Instructional Video
Khan Academy

Khan Academy: Sss to Show a Radius Is Perpendicular to a Chord That It Bisects

9th - 10th Standards
More on the difference between a theorem and axiom. Proving a cool result using SSS.