In an isosceles triangle ABC with base AC, the angle B is 3 times less than the angle at the base.

In an isosceles triangle ABC with base AC, the angle B is 3 times less than the angle at the base. Find the angle at the base of the triangle.

Since triangle ABC is isosceles, its angles at the base of A are equal. Angle BAC = BCA.

Let the values of the angle ABC = X0, then, by condition, the angle BAC = BCA = 3 * X0.

The sum of the interior angles of the triangle is 180, then (X + 3 * X + 3 * X) = 180.

5 * X = 150. X = 180/5 = 360.

Then the angle BAC = BCA = 3 * 36 = 108.

Answer: The angle at the base of the triangle is 108.