ECZ 2020 · O-Level Paper 1 — Trigonometry
The diagram below shows triangle ABC in which angle ABC = 90°. BC is produced to D. Given that tan(angle BAC) = 43, find the value of cos(angle ACD).
- A. -45
- B. 45
- C. -35
- D. 35
Verified working — step 1
Build the 3-4-5 triangle from the tangent, then handle the straight line: angle ACD is the SUPPLEMENT of angle ACB.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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