The perimeter of an isosceles triangle is 41cm and the side is 3.5cm less than the base. Find the base of the triangle.

In order to find the base of an isosceles triangle, we will compose and solve a linear equation with one variable.

We know that the perimeter of the triangle is 41 cm. And the side is 3.5 cm less than the base.

We introduce a variable, denoting by it x cm the base of the triangle, then (x – 3.5) cm.

Let’s remember the formula for finding the perimeter and compose the equation:

P = 2 (a + b);

2 (x + x – 3.5) = 41;

2x – 3.5 = 41: 2;

2x – 3.5 = 20.5;

2x = 20.5 + 3.5;

2x = 24;

x = 24: 2;

x = 12 cm base of the triangle.