Use the Triangle Angle Sum Theorem to find the measure of the third angle if the first and second angle measure 63°
and 40°
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°.