One common mistake that students in Year 7 math make is mixing up congruent and similar shapes. Let’s clear that up!

Congruent Shapes:

• Congruent shapes are exactly the same in both shape and size.
• If you can put one shape on top of the other and they fit perfectly, then they are congruent.
• You can check this using the SSS (Side-Side-Side) method, which means all the sides of the shapes are the same length.

Similar Shapes:

• Similar shapes look the same but can be different in size.
• Their angles are the same, and the sides are in the same ratio.
• A simple rule is that for two triangles to be similar, any two angles need to be the same (this is called the AA rule).

Another confusion is thinking that making a shape bigger or smaller changes if they are congruent. When you scale a shape, it becomes similar, not congruent.

Knowing these differences can really help you when solving problems with shapes!