Step 7 Objective

Enlarge 2-D shapes, given a centre of enlargement and a positive whole-number scale factor.

Examples of what pupils should know and be able to do

Probing questions

What changes when you enlarge a shape?

What stays the same?

What information do you need to complete a given enlargement?

If someone has completed an enlargement how would you find the centre and the scale factor?

When drawing an enlargement, what strategies do you use to make sure your enlarged shape will fit on the paper?

What if pupils find this a barrier?

Use dynamic geometry software to show an object and its enlarged image (using positive whole-number scale factors). Move the centre of enlargement and ask pupils to describe what is happening to the image. What stays the same? What changes?

Give pupils examples of enlargements with mistakes in them. Ask them to identify the mistakes and complete a correct enlargement.

Further information is given in TMM from L5: Shape and space pp. 19-23.