Question

Two angles are supplementary. One angle measures 9x+9 degrees and the other measures 7x-5 degrees. Determine the measure of both angles.

Answer 1

108º and 72º

1) If two angles are supplementary then

α+β =180º

2) So we can write out:

(9x +9) + (7x -5) = 180º

9x+7x +9-5 = 180º

16x +4 = 180º

16x = 176º

16x/16 =176/16

x= 11

2.2) If x= 11 then we can plug into that and find out the measures of those angles this way:

9(11) +9 = 99 +9 = 108º

7(11) -5 = 77 -5 = 72º

3) Hence, the angles are 108º and 72º, note that 108 +72 = 180º