Given an isosceles triangle, the apex angle is 40 degrees. What is the angle at the base?

Given an isosceles triangle, the apex angle is 40 degrees. What is the angle at the base? In your answer, indicate one-seventh of the angle.

Finding the angles at the base of an isosceles triangle
the angles at the base of an isosceles triangle are equal, that is, angle A = angle C;
the sum of the degree measures of all angles of the triangle is 180 degrees, that is, angle A + angle C + angle B = 180 degrees
angle B = 40 degrees;
angle A + angle C = (180 – 40) = 140 degrees;
angle A = angle C = 140 degrees: 2 = 70 degrees.
Answer: The degree measure of each of the angles at the base of this isosceles triangle is 40 degrees.