Answer: ∠R = 137°
Explanation:
The opposite angles of a quadrilateral are supplementary (equal to 180°).
Since ∠P and ∠R are opposite angles, their sum is 180°
∠P + ∠R = 180°
y + 3y + 8 = 180
4y + 8 = 180
4y = 172
y = 43
∠R = 3y + 8
= 3(43) + 8
= 129 + 8
= 137