Ratio and proportion

  • Pent
    problem

    Pent

    Age
    14 to 18
    Challenge level
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    The diagram shows a regular pentagon with sides of unit length. Find all the angles in the diagram. Prove that the quadrilateral shown in red is a rhombus.
  • Off the Cuff
    problem

    Off the Cuff

    Age
    11 to 14
    Challenge level
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    Can you work out the ratio of shirt types made by a factory, if you know the ratio of button types used?
  • Slippage
    problem

    Slippage

    Age
    14 to 16
    Challenge level
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    A ladder 3m long rests against a wall with one end a short distance from its base. Between the wall and the base of a ladder is a garden storage box 1m tall and 1m high. What is the maximum distance up the wall which the ladder can reach?
  • Square Ratio
    problem

    Square Ratio

    Age
    14 to 16
    Challenge level
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    A square is divided into four rectangles and a square. Can you work out the ratio of the side lengths of the rectangles?
  • Double Cover
    problem

    Double Cover

    Age
    11 to 14
    Challenge level
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    Weekly Problem 3 - 2007
    What is the ratio of the area of the table covered twice, to the uncovered area?
  • Pythagoras’ Comma
    problem

    Pythagoras' Comma

    Age
    14 to 16
    Challenge level
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    Using an understanding that 1:2 and 2:3 were good ratios, start with a length and keep reducing it to 2/3 of itself. Each time that took the length under 1/2 they doubled it to get back within range.

  • Eight Ratios
    problem

    Eight Ratios

    Age
    14 to 16
    Challenge level
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    Two perpendicular lines lie across each other and the end points are joined to form a quadrilateral. Eight ratios are defined, three are given but five need to be found.
  • Tyre Wear
    problem

    Tyre Wear

    Age
    11 to 14
    Challenge level
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    A car with 5 tyres (four road tyres and a spare) travelled 30,000 km. All 5 tyres were used equally. How many kilometres' wear did each tyre receive?
  • Striking gold
    problem

    Striking Gold

    Age
    16 to 18
    Challenge level
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    Investigate some of the issues raised by Geiger and Marsden's famous scattering experiment in which they fired alpha particles at a sheet of gold.
  • Reductant ratios
    problem

    Reductant Ratios

    Age
    16 to 18
    Challenge level
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    What does the empirical formula of this mixture of iron oxides tell you about its consituents?