Instructional Video
Khan Academy

Khan Academy: Triangles: Congruent Triangles and Sss

9th - 10th Standards
This video tutorial explains how to use triangle congruence to identify measures of corresponding sides and angles in triangles. Defines side-side-side (SSS) postulate.
Instructional Video
Khan Academy

Khan Academy: Basic Triangle Proofs Module Example 2

9th - 10th Standards
A video proving that the given triangles are congruent by ASA.
Instructional Video
Khan Academy

Khan Academy: Using Similar & Congruent Triangles

9th - 10th Standards
Sal uses the similarity of triangles and the congruence of others in this multi-step problem to find the area of a polygon.
Instructional Video
Sophia Learning

Sophia: Sas Triangle Congruence: Lesson 1

9th - 10th Standards
This lesson will explain that demonstrating that two pairs of sides are equal in length and that the included angles are equal will show that two triangles are congruent. It is 1 of 5 in the series titled "SAS Triangle Congruence." [1:48]
Instructional Video
Sophia Learning

Sophia: Equilateral Triangle Interior Angles Practice Problems: Lesson 2

9th - 10th Standards
This lesson will provide practice problems that involve solving for unknown angle and side measures of equilateral triangles. It is 2 of 5 in the series titled "Equilateral Triangle Interior Angles Practice Problems."