Ratio and proportion

  • From all corners
    problem

    From all corners

    Age
    14 to 16
    Challenge level
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    Straight lines are drawn from each corner of a square to the mid points of the opposite sides. Express the area of the octagon that is formed at the centre as a fraction of the area of the square.
  • Same Height
    problem

    Same height

    Age
    14 to 16
    Challenge level
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    A trapezium is divided into four triangles by its diagonals. Can you work out the area of the trapezium?
  • Do unto Caesar
    problem

    Do unto Caesar

    Age
    11 to 14
    Challenge level
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    At the beginning of the night three poker players; Alan, Bernie and Craig had money in the ratios 7 : 6 : 5. At the end of the night the ratio was 6 : 5 : 4. One of them won $1 200. What were the assets of the players at the beginning of the evening?

  • Around and Back
    problem

    Around and back

    Age
    14 to 16
    Challenge level
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    A cyclist and a runner start off simultaneously around a race track each going at a constant speed. The cyclist goes all the way around and then catches up with the runner. He then instantly turns around and heads back to the starting point where he meets the runner who is just finishing his first circuit. Find the ratio of their speeds.
  • Semi-Square
    problem

    Semi-square

    Age
    14 to 16
    Challenge level
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    What is the ratio of the area of a square inscribed in a semicircle to the area of the square inscribed in the entire circle?
  • Rati-o
    problem

    Rati-o

    Age
    11 to 14
    Challenge level
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    Points P, Q, R and S each divide the sides AB, BC, CD and DA respectively in the ratio of 2 : 1. Join the points. What is the area of the parallelogram PQRS in relation to the original rectangle?
  • Hello Again
    problem

    Hello again

    Age
    11 to 14
    Challenge level
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    Anne completes a circuit around a circular track in 40 seconds. Brenda runs in the opposite direction and meets Anne every 15 seconds. How long does it take Brenda to run around the track?
  • Bus Stop
    problem

    Bus stop

    Age
    14 to 16
    Challenge level
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    Two buses leave at the same time from two towns Shipton and Veston on the same long road, travelling towards each other. At each mile along the road are milestones. The buses' speeds are constant and in the ratio 5 to 4. The buses travel to and fro between the towns. What milestones are at Shipton and Veston?
  • Televisual Technology
    problem

    Televisual technology

    Age
    14 to 16
    Challenge level
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    If a new and an old television have screens of the same area, what is the ratio of their widths?
  • Half a Triangle
    problem

    Half a triangle

    Age
    14 to 16
    Challenge level
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    Construct a line parallel to one side of a triangle so that the triangle is divided into two equal areas.