In an isosceles triangle, the base is 0.4 of the lateral side. Find the sides of a triangle if its perimeter is 36 cm.

In order to solve this problem, we need to compose and solve an equation.

Let x be the side.

y is the base of an isosceles triangle.

y = 0.4x.

Perimeter of a triangle = x + x + y = 36.

Find x.

x + x + y = 36.

x + x + 0.4x = 36.

2.4x = 36.

x = 36 / 2.4.

x = 15 – the length of the side.

y = 15 * 0.4 = 6 – base length.

Answer: 15 cm and 6 cm.