Answer:
(4y + 6) + (7y -7) + (20y -11) = 360°
31y -12 = 360°
31y = 372°
y = 12
Arc BC = (4y + 6) + (7y -7)
Arc BC = 4*12 +6 + 7*12 -7
Arc BC = 54 +77
Arc BC = 131°
Step-by-step explanation:
