32Base angles of isosceles triangle

The angle at the top of an isosceles triangle is 40°. Find each of the two base angles.

Each base angle is 70°. Since the triangle is isosceles, the two base angles are equal, so 40 + x + x = 180 gives 2x = 140, and x = 70. Check: 40 + 70 + 70 = 180.