Question

18. The supplement of an angle of 72° is an angle measuring

A. 144°.
B. 18°.
C. 108°.
D. 288°.

Answer 1

To find a supplement angle, take 180 degrees (angle of a straight line) and subtract your given angle. 180 - 72 = 108

Your answer is C

Answer 2

Answer: OPTION C.

Explanation:

First, it is important to remember the definition of "Suplementary angles".

By definition, two angles are supplementary if they add up 180 degrees.

Therefore, the measure of the supplement angle of 72 degrees can be found by setting up the following expression:

`x+72\°=180\°`

Being "x" the measure of the supplement angle of 72 degrees.

Finally, you need to solve for "x":

`x=180\°-72\°\\\\x=108\°`

This matches with the option C.