You may also like

problem icon

Clock Hands

This investigation explores using different shapes as the hands of the clock. What things occur as the the hands move.

problem icon

Transformation Tease

What are the coordinates of this shape after it has been transformed in the ways described? Compare these with the original coordinates. What do you notice about the numbers?

problem icon

Penta Play

A shape and space game for 2,3 or 4 players. Be the last person to be able to place a pentomino piece on the playing board. Play with card, or on the computer.

Sorting Symmetries

Stage: 2 Challenge Level: Challenge Level:1

Sorting Symmetries


Naomi has a triangle which is blue on one side and yellow on the other. It has a dot in one corner on each side.
How many ways are there of posting this triangle through a triangular shaped slot? (You may like to use the interactivity from our Turning Triangle problem to help you.)

Full Size Version


This text is usually replaced by the Flash movie.

All these ways of posting the triangle are different. They can be called symmetries of the triangle. Can you work out a way to describe each one? You might like to choose a symbol for each.

Naomi finds that she can turn the triangle and then flip the triangle vertically so that she gets another symmetry. What might the triangle have looked like before she flipped it vertically, and what might it look like afterwards?

Why do this problem?


Possible approach

The difference between the process of finding the symmetries and the end product of a particular transformation will probably need emphasising.

Key questions


Possible extension


Possible support