find the measure of angel R in quadrilateral RSTW if the measure of angle R= 2x, the measure of angle S= x-7, the measure of angle T= x+5, and the measure of angle W= 30.

Answer 1

The angles of a quad add up to 360º
so
2x + x-7 + x+5 + 3- = 360

solve for x

Answer 2

Cyclic quads