Pythagoras' theorem

  • A black goat with horns and white facial markings.
    problem

    The Old Goats

    Age
    11 to 14
    Challenge level
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    A rectangular field has two posts with a ring on top of each post. There are two quarrelsome goats and plenty of ropes which you can tie to their collars. How can you secure them so they can't fight each other but can reach every corner of the field?

  • Rectangle Dissection
    problem

    Rectangle Dissection

    Age
    11 to 14
    Challenge level
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    Weekly Problem 2 - 2009
    The 16 by 9 rectangle is cut as shown. Rearrange the pieces to form a square. What is the perimeter of the square?

  • A chordingly
    problem

    A Chordingly

    Age
    11 to 14
    Challenge level
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    Find the area of the annulus in terms of the length of the chord which is tangent to the inner circle.

  • Babylon numbers
    problem

    Babylon Numbers

    Age
    11 to 18
    Challenge level
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    Can you make a hypothesis to explain these ancient numbers?
  • Fitting In
    problem

    Fitting In

    Age
    14 to 16
    Challenge level
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    The largest square which fits into a circle is ABCD and EFGH is a square with G and H on the line CD and E and F on the circumference of the circle. Show that AB = 5EF. Similarly the largest equilateral triangle which fits into a circle is LMN and PQR is an equilateral triangle with P and Q on the line LM and R on the circumference of the circle. Show that LM = 3PQ

  • Star Gazing
    problem

    Star Gazing

    Age
    14 to 16
    Challenge level
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    Find the ratio of the outer shaded area to the inner area for a six pointed star and an eight pointed star.

  • Out of the Window
    problem

    Out of the Window

    Age
    14 to 16
    Challenge level
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    Find out how many pieces of hardboard of differing sizes can fit through a rectangular window.

  • Right Angled Possibilities
    problem

    Right Angled Possibilities

    Age
    14 to 16
    Challenge level
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    If two of the sides of a right-angled triangle are 5cm and 6cm long, how many possibilities are there for the length of the third side?

  • Under the Ribbon
    problem

    Under the Ribbon

    Age
    14 to 16
    Challenge level
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    A ribbon is nailed down with a small amount of slack. What is the largest cube that can pass under the ribbon ?

  • Tetromino Diagonal
    problem

    Tetromino Diagonal

    Age
    14 to 16
    Challenge level
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    Can you calculate the length of this diagonal line?