Maths: Carroll diagrams

Our homework was quite easy if we thought about the two questions separately. First decide whether the shape is a polygon or not. If it is, it goes on the left side of the diagram. Then decide if the shape is a quadrilateral or not. That tells us whether to put it at the top or the bottom. Remember:

• a polygon has straight sides only, and


• a quadrilateral has four straight sides.

Can you explain why the top right of the diagram must always be empty?

The second diagram has different titles. Again, think about the two questions separately. First decide whether the shape is regular (all sides the same length). That tells us whether it goes on the left or the right of the diagram. Then decide whether it is a triangle or not.

Today's classwork exercise was to sort the shapes shown on the board above. Yet again there are two questions. Look at the titles of the diagram to see what the questions are. Are all the shapes correctly placed? Check them carefully.