Use the Triangle Angle Sum Theorem to find the measure of the third angle if the first and second angle measure 63° and 40° .(1 point) °
The Triangle Angle Sum Theorem states that the sum of all three angles in a triangle is always 180°.
Therefore, to find the measure of the third angle, we need to subtract the sum of the first and second angle from 180°.
Let the measure of the third angle be x°.
180° - (63° + 40°) = 180° - 103° = 77°
Therefore, the measure of the third angle is 77°.