Look at the following triangles drawn on x/y-coordinate axes.

 

 

Shape A has been reflected in the x-axis to land on shape B.

 

This has been done by moving each corner across the mirror line, the same distance beyond.

 

Look at the following L-shapes drawn on x/y-coordinate axes.

 

 

Shape A has been reflected in the y-axis to land on shape B.

This has been done by moving each corner across the mirror line, the same distance beyond.

 

Example

Look at the triangles on this coordinate grid.

On which triangle does triangle D land when it is reflected in the y-axis?

 

 

Answer

Triangle D lands on triangle A when it is reflected in the y-axis.

 

 Be careful not to get your y-axis confused with your x-axis!

The x-axis is the horizontal one and the y-axis is vertical.

 

NB Triangle D lands on triangle K when it is reflected in the x-axis.

 

Are you ready to give this a go?