Question

what is the answer?
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Answer 1

Answer:

angle AOC + AOB = 180° [ linear pair ]

AOC + 60° = 180°

=> AOC = 180° - 60°

=> AOC = 120°

Angle ACO = 60° /2[ Angle in circumference is half at angle at center ]

ACO = 30°

Angle CAB = 90° [ angle in semicircle ]

in Triangle ACB

90° + 30° + ABC = 180°

=> ABC = 180°- 120°

=> ABC = 60°