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Tessellating Triangles

Stage: 2 Challenge Level: Challenge Level:1

Equilateral triangles have three sides the same length and three angles the same. Can you make them fit together to cover the paper without any gaps between them? This is called 'tessellating'. red triangle.

What about triangles with two equal sides? These are isosceles triangles.

lilac isosceles triangle. pink isosceles triangle.

Can you tessellate all isosceles triangles?

Now try with right angled triangles. These have one right angle or 90 degree angle.

A blue, red and green right-angled triangle.

Some triangles have sides that are all different. Can you tessellate these?

A green and blue triangle.

Could you tessellate any triangle?


The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice. More information on many of our other activities can be found here.
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NRICH is part of the family of activities in the Millennium Mathematics Project.