Pythagoras' theorem

  • Crescents and triangles
    problem

    Crescents and triangles

    Age
    14 to 16
    Challenge level
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    Can you find a relationship between the area of the crescents and the area of the triangle?
  • 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?
  • Take a square
    problem

    Take a square

    Age
    14 to 16
    Challenge level
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    Cut off three right angled isosceles triangles to produce a pentagon. With two lines, cut the pentagon into three parts which can be rearranged into another square.
  • Cutting a Cube
    problem

    Cutting a cube

    Age
    11 to 14
    Challenge level
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    A half-cube is cut into two pieces by a plane through the long diagonal and at right angles to it. Can you draw a net of these pieces? Are they identical?
  • In a Spin
    problem

    In a spin

    Age
    14 to 16
    Challenge level
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    What is the volume of the solid formed by rotating this right angled triangle about the hypotenuse?
  • Circumnavigation
    problem

    Circumnavigation

    Age
    14 to 16
    Challenge level
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    The sides of a triangle are 25, 39 and 40 units of length. Find the diameter of the circumscribed circle.
  • The Dodecahedron
    problem

    The dodecahedron

    Age
    16 to 18
    Challenge level
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    What are the shortest distances between the centres of opposite faces of a regular solid dodecahedron on the surface and through the middle of the dodecahedron?
  • Squ-areas
    problem

    Squ-areas

    Age
    14 to 16
    Challenge level
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    Three squares are drawn on the sides of a triangle ABC. Their areas are respectively 18 000, 20 000 and 26 000 square centimetres. If the outer vertices of the squares are joined, three more triangular areas are enclosed. What is the area of this convex hexagon?
  • Circle Scaling
    problem

    Circle scaling

    Age
    14 to 16
    Challenge level
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    Describe how to construct three circles which have areas in the ratio 1:2:3.