You may also like

problem icon

Polydron

This activity investigates how you might make squares and pentominoes from Polydron.

problem icon

Construct-o-straws

Make a cube out of straws and have a go at this practical challenge.

problem icon

Cereal Packets

How can you put five cereal packets together to make different shapes if you must put them face-to-face?

Triangle Relations

Stage: 2 Challenge Level: Challenge Level:1

Triangle Relations


Here is an isosceles triangle and an equilateral triangle:

green isosceles triangle and yellow equilateral triangle


You will need to print off and cut out the two triangles to try this problem. (Here is a sheet of them which you could print off.)

What do the two triangles have in common?

How are they related?

Why do this problem?

The beauty of this problem is that it is completely open and therefore gives children the opportunity to approach it however they like. It is a great chance for you to observe and assess what they do, having conversations as you walk around the class.

Possible approach

It might be appropriate for children to work in pairs or small groups and they will almost certainly need a cut-out copy of each triangle. (Here is a sheet of triangles which you could use.) It would be great to have other resources available for them to use should they want - for example rulers, pencils, squared paper, triangular dotty paper etc.

Pupils will come up with a variety of different findings which might relate to side lengths, area, symmetry ... For example, some children might notice that you can halve each triangle to make two smaller triangles. The resulting four smaller triangles are in fact identical. Other children might notice that the area of each triangle is the same. You might want to bring out the fact that some of the things the triangles have in common could be exemplified in different ways.