Question

In a quadrilateral STAR if angle S=120° and angle T:S:R= 5:3:7, then find the measure of angle R

Answer 1

I hope this would help you

Answer 2

angle T + angle A + angle R + angle S = 360

5a + 3a + 7a + 120 = 360

15a = 360-120

15a = 240

a = 16

angle R = 7×16

= 112 °