Answer:
86°
Step-by-step explanation:
If you draw a line segment AC, it forms the rest of right triangle ACB with the right angle at C. Then angle BAC is the complement of the given angle:
∠BAC = 90° -47° = 43°
The inscribed angle BAC intercepts arc BC, so the arc measure will be double the angle measure.
arc BC = 2·43° = 86°
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Another way to get there is to realize that arc BCA is 180°, because AB is a diameter. As above, arc AC will be double the measure of inscribed angle ABC, so arc AC has measure 94°.
arc BC = arc ACB - arc AC
arc BC = 180° -94°
arc BC = 86°
