∠ABD is formed by a tangent and a secant intersecting outside of a circle. If minor arc AC = 72° and minor arc CD = 132°, what is the measure of ∠ABD?
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Answer: 42°
Step-by-step explanation:
First, find the minor arc AD.
arc AD=360-72-123=156
Then, ∆ABD=1/2(minor arc AD- minor arc AC)
∆ABD=1/2 (156-72)
∆ABC=1/2 84
∆ABC=42°