Find the angles at the base AC of an isosceles triangle ABC if its outer angle at the vertex B is 112 degrees.

Given:
isosceles triangle ABC,
the outer angle at the vertex B is equal to 112 degrees,
Find the degree measures of angle A and angle C -?
Decision:
1) The outer angle of a triangle is equal to the sum of the degree measures of the angles of the triangle that are not adjacent to it. Then
angle A + angle C = 112 degrees;
2) Consider an isosceles triangle ABC. In an isosceles triangle, the angles at the base are equal. Therefore, the angle A = angle C = 112: 2;
angle A = angle C = 56 degrees.
Answer: 56 degrees; 56 degrees.