## Geometry: Common Core (15th Edition)

Let a be the measure of the angle. The measure of the supplement is $180-a$. Write an expression for the measure of the angle using the information given. $a=2(180-a)-12$ use the distributive property $a=360-2a-12$ $a=348-2a$ add 2a to each side $a+2a=348-2a+2a$ $3a=348$ divide each side by 3 $3a\div3=348\div3$ $a=116$