Answer:
(B) m∠BCD = 108°
Explanation:
The measure of an arc is equal to the measure of its corresponding central angle. The corresponding central angle of arc AB is angle ACB.
Therefore, if the measure of arc AB is 72°, then m∠ACB = 72°.
Angles on a straight line sum to 180°.
Assuming that AD is a straight line, then:
m∠BCD + m∠ACB = 180°
m∠BCD + 72° = 180°
m∠BCD + 72° - 72° = 180° - 72°
m∠BCD = 108°
Therefore, the measure of angle BCD is 108°.