GCSE · Angles & polygons

Interior & exterior angles of polygonsExam-style questions

Why the exterior angles of any polygon add up to 360°, where (n − 2) × 180° comes from, how regular polygons follow instantly, and the reliable route from a given interior angle back to the number of sides.

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

DifficultyAllLevel 1Level 2Level 3Level 4Level 5
  1. 1
    Here is a pattern made from 55 regular octagons and 44 squares.aThe octagons and the squares all have sides of length aa.

    Find an expression, in terms of aa, for the total area of the pattern.

    Give your answer in the form p(7+52)a2p(7 + 5\sqrt{2})a^2 where pp is an integer.

    You must show all your working.

    (5 marks)
    Level 5 · 5 marksTry it
  2. 2
    The diagram shows a quarter circle, centre OO, radius rr cm.OADr cmBCBB and CC are points on the arc ADAD so that AB=BC=CDAB = BC = CD

    By considering the length of the arc ADAD, show that

    π>62−3\pi > 6\sqrt{2 - \sqrt{3}}

    (4 marks)
    Level 5 · 4 marksTry it
  3. 3
    PP is a regular polygon with 10 sides.

    The interior angle of a regular polygon QQ is 12°12° greater than the interior angle of PP.

    Work out the number of sides of QQ.
    Level 5 · 4 marksTry it
  4. 4
    The diagram shows a regular pentagon ABCDEABCDE. The diagonals ACAC and BDBD cross at the point FF.x°ABCDEFDiagram NOT accurately drawn

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