# The perimeter of an isosceles triangle is 20 cm. The length of the lateral side is 2 times

**The perimeter of an isosceles triangle is 20 cm. The length of the lateral side is 2 times the length of the base. Calculate the lengths of the sides of this triangle.**

Given:

ABC – isosceles triangle,

AB = 2 * AC,

the ABC perimeter is 20 centimeters.

Find the lengths of the sides of the parallelogram ABC: AB, BC, AC -?

Solution:

Consider an isosceles triangle ABC. His sides at the base are equal to each other, then AB = BC = 2 * AC.

Let the length of the AC side be x centimeters, then the length of the AB side = 2 * x centimeters. We know that the ABC perimeter is 20 centimeters. Let’s make the equation:

P avs = AB + BC + AC;

20 = 2 * x + 2 * x + x;

x * (2 + 2 + 1) = 20;

5 * x = 20;

x = 20: 5;

x = 4 centimeters – the length of the base of the speaker;

4 * 2 = 8 centimeters – the lengths of the sides AB and BC.

Answer: 4 centimeters; 8 centimeters; 8 centimeters.