Answer:
FE = 30°
Step-by-step explanation:
arc FGC = arc FG + arc GB + arc BC
220° = 90° + arc GB + 70° . . substitute known values
60° = arc GB . . . . . . . . . . . . . subtract 160°
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External angle A is half the difference of arcs EG and GB:
30° = (1/2)(arc FE +90° -60°) . . . substitute known values
60° = arc FE + 30° . . . . . . . . . . . multiply by 2 and simplify
30° = arc FE . . . . . . subtract 30°
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The key to this problem is the relationship between external angle A and the measures of the arcs it subtends.
