passwella.
Menu

WAEC Mathematics 2000 Question 45

Question 45

Mensuration of Plane Shapes

The arc of a circle 50cm long, subtends an angle of 75° at the centre of the circle. Find, correct to 3 significant figures, the radius of the circle. [Take π = 22/7]

  1. A.8.74cm
  2. B.38.2 cm
  3. C.61.2 cm
  4. D.76.4cm.
Show the answer and explanation

Answer: B (38.2 cm)

Explanation

50 = 75/360 × 2 × 22/7 × r, so r = 50 × 360 × 7/(75 × 44) ≈ 38.2 cm.