Given:
m∠APB = 74°
To find:
The measure of ACB
Solution:
The measure of the central angle is congruent to the measure of the intercepted arc.
⇒ m(ar AB) = m∠APB
⇒ m(ar AB) = 74°
The complete angle of the circle is 360°.
⇒ m(ar ACB) + m(ar AB) = 360°
⇒ m(ar ACB) + 74° = 360°
Subtract 74° from both sides.
⇒ m(ar ACB) = 286°
The measure of arc ACB is 286°.