A polygon is a 2D shape made up of three or more straight lines.

A quadrilateral is a polygon that has four straight sides and four vertices.

Parallel lines are straight lines that are always the same distance apart. They never get closer together or further apart.

To decompose means to break something into parts that are the same as the original when you put them back together.

Investigate different ways of decomposing a polygon

Maths

In this unit pupils will investigate ways to compose and decompose polygons. They will investigate quadrilaterals with and without parallel and perpendicular sides. In the future unit pupil will learn perimeter as the distance around the edge of a 2D shape. They will learn perimeter is measured in units of length found by counting units and by calculating by adding the side lengths of a 2D shape.

In the prior unit pupils rotated two lines around a fixed point to make different sized angles. They identified vertices. In this unit pupils will investigate ways to compose and decompose polygons. They will investigate quadrilaterals with and without parallel and perpendicular sides.

Parallel and perpendicular sides in polygons (and perimeter)

How many pairs of parallel sides does this quadrilateral have?

The pentagon has been decomposed into three polygons. Match the name of the polygon to the correct letter.

This hexagon has been decomposed into two shapes. Select the names of the decomposed shapes.

Two lines that meet at a right angle are called __________ lines.

Look at the image. Which statements are true?

has more than one pair of perpendicular sides.

This octagon has been decomposed into 3 polygons. Match each polygon to the correct description.

Match the parts of the sentence correctly.

Which of these are properties of a rectangle?

Look at this pentagon. 
How many right angles does it have? {{ }} right angles

Look at this hexagon. 
How many right angles does it have? {{ }} right angles

This rectangle has been cut in half using a diagonal line. What shape will both halves be?

This lesson will soon be taken down.

Investigate different ways of decomposing a polygon

Lesson outcome