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 and CC are points on a circle with centre OO.

    Angle ABC=36°ABC = 36°.36°xABCODiagram NOT accurately drawn

    Work out the size of the angle marked xx. Give a reason for your answer.
    Level 2 · 3 marksTry it
  2. 2
    AA, BB, CC and DD are points on a circle.3x°(x + 20)°ABCDDiagram NOT accurately drawn

    Angle DAB=3x°DAB = 3x° and angle BCD=(x+20)°BCD = (x + 20)°.

    Work out the value of xx. Give a reason for your answer. (3 marks)
    Level 3 · 3 marksTry it
  3. 3
    AA, BB and CC are points on a circle with centre OO. Angle AOB=140°AOB = 140°.140°ABCODiagram NOT accurately drawn

    (a) Work out the size of angle ACBACB. Give a reason for your answer. (2 marks)

    (b) Work out the size of angle OABOAB. Give a reason for your answer. (2 marks)
    Level 3 · 4 marksTry it
  4. 4
    PP, QQ and RR are points on a circle with centre OO. PQPQ is a diameter.

    Angle QPR=27°QPR = 27°.27°xPQRODiagram NOT accurately drawn

    Work out the size of the angle marked xx. You must give reasons for each stage of your working.
    Level 3 · 4 marksTry it
  5. 5
    ABCDABCD is a cyclic quadrilateral.

    Angle DAB=104°DAB = 104° and angle ABC=88°ABC = 88°.104°88°xyABCDDiagram NOT accurately drawn

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

    (b) Work out the size of the angle marked yy.
    Level 3 · 4 marksTry it

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