# Isosceles Triangle

How to solve isosceles triangle problems: property, examples, and their solutions.

## Property

An isosceles triangle has

two congruent sides (legs)

and two congruent angles.

Leg: two congruent sides

Base: side that is adjacent to the congruent angles

## Example 1

The given triangle is an isosceles triangle.

So the given angles are congruent.

So 3*x* + 25 = 55.

## Example 2

The right triangle is an isosceles triangle.

So the measure of the left blue angle is 70.

The left blue angle is

the exterior angle of the left isosceles triangle.

So *x* + *x* = 70.