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WAEC Mathematics 2016 Question 37

Question 37

Mensuration of Plane Shapes

The perimeter of a sector of a circle of radius 21 cm is 64 cm. Find the angle of the sector. [Take π = 22/7]

  1. A.70°
  2. B.60°
  3. C.55°
  4. D.42°
Show the answer and explanation

Answer: B (60°)

Explanation

Arc = 64 − 42 = 22 cm. θ/360 × 2 × 22/7 × 21 = 22 gives θ/360 × 132 = 22, so θ = 60°.