How to Classify Quadrilaterals

Hi, I'm Florence. And today we're going to be looking at quadrilaterals and thinking about some key misconceptions that can arise when children are classifying shapes with four sides. So a quadrilateral is a four sided polygon, and there is one really important group of quadrilaterals that is a parallelogram. A parallelogram is every four sided shape which has two pairs of opposite sides which are parallel. So we can see here we have two pairs of parallel sides that are opposite to each other. When we think about that definition, it brings to mind quite a lot of common quadrilaterals that pupils will know. For example, the rectangle. What makes the rectangle a special kind of parallelogram is its angles. It has four right angles. So any parallelogram with four right angles is a rectangle. And again, when you tell pupils about that, they're going to immediately hopefully think of another quadrilateral. That's right, the square. So the square is in fact a special kind of rectangle, which is a really common misconception among pupils, as they can often have quite a fixed idea of what a square should look like and what a rectangle should look like. But actually, we need to be really clear with them that the square is a type of rectangle and the rectangle is a type of parallelogram. And this is another way that we can classify parallelograms. A rhombus is a parallelogram in which all four sides are equal in length. So we have an example here. And again, if you give children that definition, they should be able to make that link and see that a square is also a special kind of rhombus. So there you have it, some really key terms that children need to know when classifying quadrilaterals.