## Geometry: Common Core (15th Edition)

Remember the definition of supplementary angles. It means that the two angles add up to 180 degrees. So, set the larger angle equal to x. Therefore, the measure of the smaller angle equals 180-x. Now you can set up your proportion. $\frac{180-x}{x}$ = $\frac{5}{7}$ Cross multiply. 5x = 7(180-x) 5x=1260-7x 12x=1260 x=105 The larger angle is 105.