The angle of a sector of a circle is 108°. If the radius of the
MATHEMATICS
WAEC 1995
The angle of a sector of a circle is 108°. If the radius of the circle is 31/2cm, find the perimeter of the sector
- A. 63/5cm
- B. 64/5cm
- C. 71/10cm
- D. 133/5cm
Correct Answer: D. 133/5cm
Explanation
Perimeter of sector = \(\frac{\theta}{360°} \times 2\pi r + 2r\)
= \(\frac{108}{360} \times 2 \times \frac{22}{7} \times \frac{7}{2} + 2(\frac{7}{2})\)
= \(6 \frac{3}{5} + 7\)
= \(13 \frac{3}{5} cm\)
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