Let O be the centre of a circle. Let A, B and C lie on the circle such that \angle ABC = 153^\circ. What is the value of \angle AOC ?
- A. 54^\circ ✓
- B. 52^\circ
- C. 39^\circ
- D. 27^\circ
Correct Answer: A. 54^\circ
Explanation
The angle subtended by the major arc AC at the circumference is 153^\circ. The reflex angle at the center AOC is 2 \times 153^\circ = 306^\circ. The interior \angle AOC = 360^\circ - 306^\circ = 54^\circ.
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