Ratio and proportion

  • Orbiting Billiard Balls
    problem

    Orbiting billiard balls

    Age
    14 to 16
    Challenge level
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    What angle is needed for a ball to do a circuit of the billiard table and then pass through its original position?
  • The Rescaled Map
    problem

    The rescaled map

    Age
    14 to 16
    Challenge level
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    We use statistics to give ourselves an informed view on a subject of interest. This problem explores how to scale countries on a map to represent characteristics other than land area.
  • Rarity
    problem

    Rarity

    Age
    16 to 18
    Challenge level
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    Show that it is rare for a ratio of ratios to be rational.
  • Points in Pairs
    problem

    Points in pairs

    Age
    14 to 16
    Challenge level
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    Move the point P to see how P' moves. Then use your insights to calculate a missing length.
  • Equal Temperament
    problem

    Equal temperament

    Age
    14 to 16
    Challenge level
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    The scale on a piano does something clever : the ratio (interval) between any adjacent points on the scale is equal. If you play any note, twelve points higher will be exactly an octave on.
  • Wedge on Wedge
    problem

    Wedge on wedge

    Age
    14 to 16
    Challenge level
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    Two right-angled triangles are connected together as part of a structure. An object is dropped from the top of the green triangle where does it pass the base of the blue triangle?
  • Hexagon Slices
    problem

    Hexagon slices

    Age
    11 to 14
    Challenge level
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    Weekly Problem 37 - 2007
    This regular hexagon has been divided into four trapezia and one hexagon.... what is the ratio of the lengths of sides p, q and r?
  • Exact dilutions
    problem

    Exact dilutions

    Age
    14 to 16
    Challenge level
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    Which exact dilution ratios can you make using only 2 dilutions?
  • Scale Draw
    problem

    Scale draw

    Age
    5 to 7
    Challenge level
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    Use the grids to draw pictures to different scales.