Pythagoras' theorem

There are 108 NRICH Mathematical resources connected to Pythagoras' theorem
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?
The Fire-fighter's Car Keys
problem

The Fire-fighter's Car Keys

Age
14 to 16
Challenge level
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A fire-fighter needs to fill a bucket of water from the river and take it to a fire. What is the best point on the river bank for the fire-fighter to fill the bucket ?.
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 ?
Interior Squares
problem

Interior Squares

Age
14 to 16
Challenge level
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Calculate the ratio of areas of these squares which are inscribed inside a semi-circle and a circle.
Common Tangent
problem

Common Tangent

Age
14 to 16
Challenge level
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Two circles touch, what is the length of the line that is a tangent to both circles?
Nicely Similar
problem

Nicely Similar

Age
14 to 16
Challenge level
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If the hypotenuse (base) length is 100cm and if an extra line splits the base into 36cm and 64cm parts, what were the side lengths for the original right-angled triangle?
Spherical triangles on very big spheres
problem

Spherical triangles on very big spheres

Age
16 to 18
Challenge level
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Shows that Pythagoras for Spherical Triangles reduces to Pythagoras's Theorem in the plane when the triangles are small relative to the radius of the sphere.
Where is the dot?
problem

Where is the dot?

Age
14 to 16
Challenge level
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A dot starts at the point (1,0) and turns anticlockwise. Can you estimate the height of the dot after it has turned through 45 degrees? Can you calculate its height?
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?
Walk the Plank
problem

Walk the Plank

Age
14 to 16
Challenge level
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A rectangular plank fits neatly inside a square frame when placed diagonally. What is the length of the plank?