## Algebra: A Combined Approach (4th Edition)

The sum of the measures of the angles of a parallelogram is 360°. In the parallelogram, angles A and D have the same measure as well as angles C and B. If the measure of angle C is twice the measure of angle A, find the measure of each angle. Lets call angles A and D x, and angles C and B y. $2x+2y=360$ So, $x+y=180$ $y=2x$ $x+2x=180$ $3x=180$ $x=60°$ $y=2*60$ $y=120°$ Hence, the measure of each angle is 60°, 60°, 120°, and 120°.