An arc of a circle of radius 7.5cm is 7.5cm long. Find, correct to the...
MATHEMATICS
WAEC 2017
An arc of a circle of radius 7.5cm is 7.5cm long. Find, correct to the nearest degree, the angle which the arc subtends at the centre of the circle. [Take \(\pi = \frac{22}{7}\)]
- A. 29\(^o\)
- B. 57\(^o\)
- C. 65\(^o\)
- D. 115\(^o\)
Correct Answer: B. 57\(^o\)
Explanation
lac = \(\frac{\theta}{360}\) x 2\(\pi\)r
7.5 = \(\frac{\theta}{360}\) x 2 x \(\frac{22}{7}\) x 7.5
7.5 = \(\frac{330\theta}{2520}\)
\(\theta\) = \(\frac{7.5}{0.1309}\)
\(\theta\) = 57.29
\(\theta\) = 57 \(^o\)
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