ECZ 2022 · GCE Paper 1 — Trigonometry
In the diagram, ABC is a straight line, angle BCD = 90° and tan AB̂D = −34. Calculate the length of BD.
- A. 3 units
- B. 4 units
- C. 5 units
- D. 7 units
Verified working — step 1
Angle AB̂D is obtuse (D lies above the line, on the C side of B), so its tangent is negative. The acute angle DB̂C is its supplement, and tan DB̂C = 34. In right-angled triangle BCD this gives DC = 3 and BC = 4, so BD = √(3² + 4²) = √25 = …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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