Triangle ABC is isosceles and one of the base angles is 15° larger than the vertex angle. Find the angles.

Answer 1

Let x = the vertex angle. One base angle is 15° larger, so it is x + 15°. In an isosceles triangle, the two base angles are equal, so the other base angle is also x + 15°:

x + x + 15° + x + 15° = 180°

3x + 30 = 180

Solve for x (the vertex angle). The base angles are x + 15°.