Question

In parallelogram ABCD measure angle A=(2x) and measure angle B=(5x+5). what are the measures of the angles of the parallelogram

Answer 1

Opposite angles are equal, so we know that C=2x and D=5x+5 as well.

The sum of the interior angles of any quadrilateral is 360, so we have

$2(2x+5x+5)=2(7x+5)=360 \iff 7x+5=180 \iff 7x=175 \iff x=25$

So, the measures of the angles are

$2x=50,\quad 5x+5=130$