ECZ 2026 · GCE Paper 1 — Circle Theorems
The points A, B, C and D are on the circumference of a circle centre O such that angle OBC = 50° and angle OCD = 25°. BT is a tangent to the circle at B. Find angle BTD.
- A. 40°
- B. 45°
- C. 35°
- D. 25°
Verified working — step 1
T lies on DC produced, so angle BTD is the angle at T in triangle BCT. Get the angle at C from the straight line and the angle at B from the tangent, then use the angle sum.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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