ECZ 2025 · O-Level Paper 1 — Circle Theorems

A, B, C and D are points on the circumference of a circle with centre O, such that angle OBC = 40°, angle DCA = 32° and TR is a tangent to the circle at B. The diameter AC and chord BD intersect at X. Find angle (a) OAB.

Verified working — step 1

AC is a diameter.

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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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