# Congruence of Triangles

## Consider the two triangles ABE and JKL

Move points A, B, J or K and try to overlap the triangles. Is it possible to overlap the two triangles so that the sides of one match the sides of the other?

## Consider the ABE and MKJ triangles

Move points A, B, J or K and try to overlap the triangles. Is it possible to overlap the two triangles so that the sides of one match the sides of the other?

What if you could turn one of the triangles?

## Analysis 1

In the next construction, check the options to show the measurements of the sides and angles.

What are the characteristics of the triangles that overlap so that the sides coincide?

## CONGRUENT TRIANGLES

The triangles that overlap perfectly so that the sides coincide are congruent. In-depth explanation: Two triangles are congruent when the sides and angles of one are respectively congruent to the sides and angles of the other.

## Observation

In many cases, it is necessary to determine the sides that are congruent, without having the measure of these sides. In these cases, the references can be the angle marks. Let's look at the following case:

## Congruent sides

Which sides are congruent?

Check all that apply