10y + 7 + 3(3y + 7) = 180
10y + 7 + 9y + 21 = 180
19y + 28 = 180
19y = 180 - 28
19y = 152
y = 152/19
y = 8
Plug back into Q and S.
Q = 10y + 7
Q = 10(8) + 7
Q = 80 + 7
Q = 87
S = 3(3y + 7)
S = 9y + 21
S = 9(8) + 21
S = 72 + 21
S = 93
Without solving for x to find the other angles, we can easily see that the answer is choice C.
Answer:
P = 61°
Q = 87°
R = 119°
S = 93°
Done!
