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

1 answer

The Triangle Angle Sum Theorem states that the sum of the three angles in any triangle is always 180°.

Let's call the third angle "x".

According to the theorem, we can write an equation:

63° + 40° + x = 180°

Combining like terms, we have:

103° + x = 180°

To isolate x, we subtract 103° from both sides of the equation:

x = 180° - 103°

x = 77°

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