GCSE · Circles, arcs & sectors

Circle theoremsExam-style questions

The theorems about angles in a circle — at the centre, in a semicircle, in the same segment, and in a cyclic quadrilateral — why each is true, and the exact wording examiners require as a reason.

16 questions · GCSE (Higher) level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 2Level 3Level 4Level 5
  1. 1
    AA, BB, CC and DD are points on a circle.

    ACAC is a diameter of the circle.

    Angle BAC=27°BAC = 27°.27°ABCDDiagram NOT accurately drawn

    Work out the size of angle ADBADB.

    Give reasons for your answer. (4 marks)
    Level 4 · 4 marksTry it
  2. 2
    AA, BB, CC and DD are points on a circle, centre OO.124°OABCDAngle AOC=124°AOC = 124°

    Work out the size of angle ABCABC.

    Write down any circle theorems you use.

    (4 marks)
    Level 4 · 4 marksTry it
  3. 3
    The four vertices of rectangle PQRSPQRS lie on a circle, centre OO.11 cm6.5 cmPQRSOPQ=11PQ = 11 cm QR=6.5\qquad QR = 6.5 cm

    Work out the circumference of the circle.

    Give your answer correct to 3 significant figures.

    (4 marks)
    Level 4 · 4 marksTry it
  4. 4
    AA, BB, CC and DD are points on a circle with centre OO.

    Angle AOC=130°AOC = 130°, where AOCAOC is the angle at the centre standing on the arc ABCABC.

    ABCDABCD is a cyclic quadrilateral.

    (a) Work out the size of angle ADCADC. Give a reason for your answer.

    (b) Work out the size of angle ABCABC. Give a reason for your answer.
    Level 4 · 6 marksTry it
  5. 5
    AA, BB and CC are points on a circle with centre OO.

    The reflex angle AOB=216°AOB = 216°.216°xABCODiagram NOT accurately drawn

    Work out the size of the angle marked xx. Give a reason for your answer.
    Level 4 · 3 marksTry it

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