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Let's Investigate Triangles

Vincent and Tara are making triangles with the class construction set. They have a pile of strips of different lengths. How many different triangles can they make?

Seven Sticks

Explore the triangles that can be made with seven sticks of the same length.

Three Fingers and a Loop of String

Using a loop of string stretched around three of your fingers, what different triangles can you make? Draw them and sort them into groups.

Board Block for Two

Age 5 to 7
Challenge Level
Here's a game to play with an adult!

How do you play?
You'll need an adult to play with.
You'll also need a circular pegboard, or the interactive pegboard below:

You can also print off some pegboards from this page.
Firstly, choose the number of pegs on your board. Six might be a good choice to start with (here is a sheet of pegboards each with six pegs). Take it in turns with the adult to add a band to the board. Bands must fit round three pegs, in other words, each must make a triangle.
A band can share a peg with other bands, but the triangles must not overlap (except along the edges and pegs).
A player loses when they cannot make a triangle on their turn.

What are the winning strategies?
Once you've mastered this game, why not play to lose? How is the game affected?
Notes for adults
This game is designed to help children learn the properties of a triangle. There is also an opportunity for thinking strategically by working out what will happen in advance.

Easier version: play the game on a print-out of the pegboard so that the child can keep a record of the moves they've made.
Harder version: try increasing the number of pegs on the board. Board Block Challenge for Two offers more ideas for children to explore.

Repeat the game, aiming to find a winning strategy, then talk together about how it was found.

There's a classroom version of this game here.