Use the Triangle Angle Sum Theorem to find the measure of the third angle if the first and second angle measure 63°

Question

and 40°

Answer 1

Let the measure of the third angle be x.

According to the Triangle Angle Sum Theorem, the sum of all three angles in a triangle is always 180°.

Therefore,
63° + 40° + x = 180°

103° + x = 180°

x = 180° - 103°

x = 77°

Therefore, the measure of the third angle is 77°.