This resource has a number of activities appropriate to this topic. Shapes that can grow requires students to find scale factors by calculating how many times one shape fits into another. Areas of similar shapes is a little more advanced but ideal for extension work. Students are presented with a trapezium that has been enlarged by different scale factors. Students are required to investigate what happens to the areas of these shapes. Similar triangles presents students with a number of triangles and requires them to be grouped into sets of similar ones.
Activity 5 explores fractional scale factors. Activity 12 explores negative scale factors. Both sets could be used as part of the same lesson to make the connection clear to learners. The language used for negative scale factors may need some explaining.
Activity 7 investigates further the concepts of congruence and similarity in relation to area in similar figures. Activity 11 formalises the learning from the previous example, includes circles and real contexts. Activity 13 Similar Solids takes this one step further by extending the investigation to look at the relationship between the volumes of similar solids.