Answer:
160°
Step-by-step explanation:
Sum of interior angles of a triangle = 180°
Angles on a straight line = 180°
⇒ m∠A + m∠B = exterior m∠C
⇒ (5x - 10) + (12x) = (16x)
⇒ 5x - 10 + 12x = 16x
⇒ 17x - 10 = 16x
⇒ 17x = 16x + 10
⇒ x = 10
Therefore, exterior m∠C = 16(10) = 160°
