"Find the measures of two supplementary angles if their measures are 3:7
Since the ratio is 3:7 we can assume that the angles are equal to 3x and 7x?"
3x+7x=180° (180° since a line is equal to that)
then solve
10x=180
x=18
then substitute x=18 in 3x and 7x
3x=54°. 4x=126°
126° and 54°