WAEC Mathematics 2019 Objective — Question 39

Question 39 of 145 from the West African Examinations Council (WAEC) Mathematics 2019 Objective paper, with the correct answer and a full explanation.

39. In the diagram above, O is the centre of the circle of radius 18cm. If ∠ZXY = 70°, calculate the length of arc ZY. [Take π = 22/7]

• A. 11cm
• B. 22cm
• C. 44cmCorrect
• D. 80cm

Explanation

The angle at the centre is twice the angle at the circumference: θ = 2(70°) = 140°. Length of arc ZY = (θ/360)×2πr = (140/360)×2×(22/7)×18 = 110.880/2520×1000... simplified: = 44cm.

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