Answer:
69°, 69°, and 42°
Explanation:
Isosceles triangles have three angles -- one vertex angle and two base angles.
The base angles have the same measure and the vertex angle has a different measure.
Remember all triangles' interior angles sum to 180°.
If the vertex angle is 42°, then the two base angles combined are:
180° - 42° = 138°
Since the base angles are the same, each base angle is:
138° ÷ 2 = 69°
Therefore the angles in the triangle measure 69°, 69°, and 42°.