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) ABT.
- A. 40°
- B. 50°
- C. 80°
- D. 130°
Verified working — step 1
Two theorems chain together here: the isosceles triangle made by two radii, then the tangent-chord (alternate segment) angle.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.
Have a different question?
Search it — if it is from a past paper or a school mock, chances are we have it worked out, or one that uses the same method.
Search any past-paper question