Rotation Symmetry in Triangles
In this activity we are going to look at the rotation symmetry of triangles.
What order of rotation symmetry does an equilateral triangle have?
The red triangle has been rotated about its centre by the angle given to create the blue triangle.
By moving the orange point, change the angle to place the blue triangle exactly over the red triangle.
How many rotations can be found this way? How does this tell us the order of rotational symmetry? Why is this the case?
Now reset the activity by pressing the button in the top right of the activity.
This time, change the red equilateral triangle into a red isosceles triangle by moving the vertices (corners).
What order of rotational symmetry does an isosceles triangle have?
Check by moving the line as above.
Now try the same thing with other types of triangles. Can you name all the types of trianlges you make? What order of rotational symmetry does each have?
What order of rotation symmetry does an equilateral triangle have?
The red triangle has been rotated about its centre by the angle given to create the blue triangle.
By moving the orange point, change the angle to place the blue triangle exactly over the red triangle.
How many rotations can be found this way? How does this tell us the order of rotational symmetry? Why is this the case?
Now reset the activity by pressing the button in the top right of the activity.
This time, change the red equilateral triangle into a red isosceles triangle by moving the vertices (corners).
What order of rotational symmetry does an isosceles triangle have?
Check by moving the line as above.
Now try the same thing with other types of triangles. Can you name all the types of trianlges you make? What order of rotational symmetry does each have?
Rotation Symmetry in Triangles
Created with GeoGebra 
Ideas for Teachers
This activty gets the pupils to see the relationship between rotational symmetry and angles. It should also become clear that every shape has at least order one rotational symmetry (important terminology that needs to be introduced) since an angle of 0 degrees can be used.
Demonstrating from the front can be effective, but the real power behind this activity is when the pupils can get their hands on, and explore themselves.
This activty gets the pupils to see the relationship between rotational symmetry and angles. It should also become clear that every shape has at least order one rotational symmetry (important terminology that needs to be introduced) since an angle of 0 degrees can be used.
Demonstrating from the front can be effective, but the real power behind this activity is when the pupils can get their hands on, and explore themselves.
If you like the page then tweet the link using the button on the right.

If you have found interactivemaths.com a useful website, then please support it by making a donation using the button opposite.

