ECZ 2012 · O-Level Paper 1 — Trigonometry

In the diagram, AC = 10 cm, BC = 5 cm and angle ACB = 60 degrees. Given that sin 60 = 0.866, cos 60 = 0.5 and tan 60 = 1.73, calculate the value of (AB)².

Verified working — step 1

By the cosine rule, (AB)² = 10² + 5² - 2(10)(5)cos 60 = 100 + 25 - 100(0.5) = 125 - 50 = …

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Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.

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