Lesson: Congruence of Triangles: SSS, SAS, and RHS Mathematics • 8th Grade

In this lesson, we will learn how to prove that two triangles are congruent using either the side-side-side (SSS), the side-angle-side (SAS), or the right angle-hypotenuse-side (RHS) criterion.

Lesson Plan

Students will be able to

recognize that SSS, SAS, and RHS are conditions of congruency but that AAA is not,
recognize whether SSS, SAS, or RHS can be used to prove that two given triangles are congruent,
understand that the condition of congruency for two right triangles is not necessarily RHS,
solve a word problem or a more complex geometric problem using SSS, SAS, or RHS.

Lesson Video

Lesson Playlist

01:52

Lesson Worksheet

Q1:

In the given figure, triangle and triangle have two equal sides and share one equal angle. Are triangles and congruent?

Q2:

Given that is the midpoint of in the given figure, without referencing angles, which congruence criteria could you use to prove triangles and are congruent?

Q3:

The figure shows triangles and .

Are the two triangles congruent?

Justify your answer with one of the following reasons.