ECZ 2021 · O-Level Paper 2 · Question 12 — Trigonometry
Question from ECZ 2021 · O-Level Paper 2 · Question 12
(a) The diagram below shows triangle ABC in which AB = 11.5 m, BC = 7.2 m and AC = 15.1 m. Calculate
(a(i)) angle ABC,[5]
Verified working — step 1
All three sides known, so cosine rule for the angle:(a(ii)) the area of triangle ABC,[2]
Verified working — step 1
Two sides and the included angle at B: Area = (12)(AB)(BC) sin(ABC)(a(iii)) the shortest distance from B to AC.[2]
Verified working — step 1
The shortest distance is the perpendicular height h from B onto AC.(b) Solve the equation 15 tan θ = 14 for 180° ≤ θ ≤ 270°.[1]
Verified working — step 1
tan θ = 1415 = 0.9333, related acute angle 43.0°.(c) Simplify 39x328y4 ÷ 65x556y5.[2]
Verified working — step 1
Multiply by the reciprocal: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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