In an isosceles triangle, one of the angles is 125 degrees. Find the sum of the angles at the base.

We know that in an isosceles triangle, the apex angle is 125 °. In order to find the angle at the base, let’s recall the theorem on the sum of the angles of a triangle and the properties of the angles at the base of an isosceles triangle.

The triangle sum theorem says that the sum of the angles of a triangle is 180 °.

In an isosceles triangle, the angles at the base are equal.

Let’s find the sum of the angles of a triangle at the base. To do this, from 180 ° we must subtract the degree measure of the angle at the vertex:

180 ° – 125 ° = 55 °.

Answer: 55 ° is the sum of the angles at the base.