Identify Reflected Shapes in a Slanted Mirror Line

A line of symmetry divides a shape into two matching parts, which will overlap each other exactly when folded along the line of symmetry.

 

When we complete shapes to make them symmetrical, we must reflect each corner in the line of symmetry.

In this activity, the lines of symmetry will be slanting.

 

Make sure that you reflect carefully. Each corner moves in a direction which is at right angles to the fold.

 

Look at this shape.

 

 

To complete the symmetry of the shape, we reflect each corner in the line m.

Notice that the blue lines are at right angles to the red line of symmetry m.

 

 

 

The next shape has been completed incorrectly.

Notice that the blue lines are not at right angles to the red line of symmetry m.

 

 

 

This is how it should be completed.

Notice that the blue lines are at right angles to the red line of symmetry m.

 

 

 

This is a very tricky thing to spot, so don't worry if you find it hard. It will becomes easier the more you practise.

 

You can look back at this example at any point during the activity - just click on the red help button that will appear on the screen.

 

Good luck!