ECZ 2020 · O-Level Paper 1 — Mensuration
Calculate the radius of a semicircle whose area is 77 cm². [Take π to be 227.]
- A. 3.5 cm
- B. 7 cm
- C. 14 cm
- D. 49 cm
Verified working — step 1
Area of a semicircle = πr²/2. So (227)r²/2 = 77 ⇒ (227)r² = 154 ⇒ r² = 154 × 722= 49 ⇒ r = …The full step-by-step working and final answer are included with Premium — checked against ECZ marking standards.
Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.
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