Answer:
15
Step-by-step explanation:
m∠Q = 93 °
m∠R = 87 °
Part A: 3:2 or 3 to 2
Part B: 18 + 12 = 30
(x + 8) × 4 = 21 × 4
Explanation:
x + 8 = 21
21 - 8 = 13
(13 + 8) × 4 = 21 × 4
21 × 4 = 21 × 4
84 = 21 × 4
84 = 84