Circle TheoremsCambridge IGCSE Maths: Subtopic test
10 questions, 26 marks
Cambridge IGCSE Maths
Circle Theorems
Total 26 marks
Name
Class
Date
- 1A circle with centre O has points A, B and C on its circumference, where AC is a diameter. A tangent line touches the circle at point D.(a)Points A, B and C lie on a circle with centre O, where AC is a diameter. If angle ABC is the angle subtended at B by the diameter AC, what is the size of angle ABC?[1 mark]
- A
- B
- C
- DCannot be determined
(b)A tangent to the circle touches at point D, and OD is a radius drawn to that point. What is the size of the angle between the tangent and OD?[1 mark]- A
- B
- C
- D
(c)Given angle BAC = in triangle ABC (where AC is a diameter), find angle BCA.[1 mark]- A
- B
- C
- D
Total for question 1: 3 marks
- 2Points P, Q, R and S lie on a circle with centre O. The angle at the centre, angle POR, is , and PQRS forms a cyclic quadrilateral.(a)Points P, Q and R lie on a circle with centre O. The angle at the centre, angle POR, is . Find angle PQR, the angle at the circumference subtended by the same arc PR, giving a geometric reason.[2 marks](b)PQRS is a cyclic quadrilateral. Given that angle PQR = (from part (a)), find angle PSR, giving a geometric reason.[2 marks]
Total for question 2: 4 marks
- 3A circle with centre O contains two chords, EF and GH, and a tangent from an external point J touching the circle at two points.(a)Two chords, EF and GH, of a circle with centre O, are both known to be equidistant from O. Given EF = 6 cm, find the length of GH, giving a geometric reason.[3 marks](b)From an external point J, two tangents are drawn to the circle, touching at points K and L. Given JK = 9 cm, find JL, and state the two geometric facts used to justify your answer.[3 marks]
Total for question 3: 6 marks
- 4A circle has a tangent touching at point T, with chord TW drawn from T, and point V on the circle in the alternate segment. A further point U also lies on the circle, forming cyclic quadrilateral TWVU.(a)A tangent touches a circle at point T. A chord TW is drawn from T, and angle between the tangent and chord TW is . A point V lies on the circle in the alternate segment. Using the alternate segment theorem, find angle TVW, giving a full geometric reason.[4 marks](b)TWVU is a cyclic quadrilateral inscribed in the same circle, with vertices in the order T, W, V, U. Angle TVW (from part (a)) and angle WTU . Find angle WVU, and hence find angle TVU, showing all reasoning.[4 marks](c)Explain, using circle theorem vocabulary, why angle TVW (found in part (a)) and the angle at the centre subtended by the same arc TW would be related by a factor of two, and calculate that centre angle.[5 marks]
Total for question 4: 13 marks
End of questions