Use the Triangle Angle Sum Theorem to find the measure of the third angle if the first and second angle measure 63° and 40° .
The Triangle Angle Sum Theorem states that the sum of the measures of the angles in a triangle is always 180°.
Let's denote the measure of the third angle as x.
According to the theorem, we can write the equation:
63° + 40° + x = 180°
Combine like terms:
103° + x = 180°
Subtract 103° from both sides:
x = 180° - 103°
x = 77°
Therefore, the measure of the third angle is 77°.