Triangles

There are 117 NRICH Mathematical resources connected to Triangles

Square split into a triangle and trapezium

problem

Favourite

Tangram tangle

Age

5 to 7

Challenge level

If you split the square into these two pieces, it is possible to fit the pieces together again to make a new shape. How many new shapes can you make?

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Triangle in a triangle

Age

14 to 16

Challenge level

Can you work out the fraction of the original triangle that is covered by the inner triangle?

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Favourite

Four triangles puzzle

Age

5 to 11

Challenge level

Cut four triangles from a square as shown in the picture. How many different shapes can you make by fitting the four triangles back together?

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Favourite

Triangle animals

Age

5 to 7

Challenge level

How many different ways can you find to join three equilateral triangles together? Can you convince us that you have found them all?

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Favourite

Repeating patterns

Age

5 to 7

Challenge level

Try continuing these patterns made from triangles. Can you create your own repeating pattern?

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Favourite

Transformations on a pegboard

Age

7 to 11

Challenge level

How would you move the bands on the pegboard to alter these shapes?

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Favourite

More transformations on a pegboard

Age

7 to 11

Challenge level

Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.

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Favourite

Of all the areas

Age

14 to 16

Challenge level

Can you find a general rule for finding the areas of equilateral triangles drawn on an isometric grid?

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Favourite

Colouring triangles

Age

5 to 7

Challenge level

Explore ways of colouring this set of triangles. Can you make symmetrical patterns?

problem

Favourite

Cut it out

Age

7 to 11

Challenge level

Can you dissect an equilateral triangle into 6 smaller ones? What number of smaller equilateral triangles is it NOT possible to dissect a larger equilateral triangle into?

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For younger learners

Triangles

Tangram tangle

Triangle in a triangle

Four triangles puzzle

Triangle animals

Repeating patterns

Transformations on a pegboard

More transformations on a pegboard

Of all the areas

Colouring triangles

Cut it out