Pythagoras' theorem

  • Centre Square
    problem

    Centre Square

    Age
    14 to 16
    Challenge level
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    What does Pythagoras' Theorem tell you about the radius of these circles?

  • Rectangular Pyramids
    problem

    Rectangular Pyramids

    Age
    14 to 18
    Challenge level
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    Is the sum of the squares of two opposite sloping edges of a rectangular based pyramid equal to the sum of the squares of the other two sloping edges?
  • Xtra
    problem

    Xtra

    Age
    14 to 18
    Challenge level
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    Find the sides of an equilateral triangle ABC where a trapezium BCPQ is drawn with BP=CQ=2 , PQ=1 and AP+AQ=sqrt7 . Note: there are 2 possible interpretations.

  • Chord
    problem

    Chord

    Age
    16 to 18
    Challenge level
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    Equal touching circles have centres on a line. From a point of this line on a circle, a tangent is drawn to the farthest circle. Find the lengths of chords where the line cuts the other circles.

  • Little and Large
    problem

    Little and Large

    Age
    16 to 18
    Challenge level
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    A point moves around inside a rectangle. What are the least and the greatest values of the sum of the squares of the distances from the vertices?

  • Square Pair Circles
    problem

    Square Pair Circles

    Age
    16 to 18
    Challenge level
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    Investigate the number of points with integer coordinates on circles with centres at the origin for which the square of the radius is a power of 5.

  • 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?

  • Pythagoras mod 5
    problem

    Pythagoras Mod 5

    Age
    16 to 18
    Challenge level
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    Prove that for every right angled triangle which has sides with integer lengths: (1) the area of the triangle is even and (2) the length of one of the sides is divisible by 5.

  • Incircles Explained
    article

    Incircles Explained

    This article is about triangles in which the lengths of the sides and the radii of the inscribed circles are all whole numbers.
  • All is Number
    article

    All Is Number

    Read all about Pythagoras' mathematical discoveries in this article written for students.