WALT: Understand area; draw shapes which have the same area

• L x W • Multiply the two together • Count the squares

Area is the space occupied (taken up by) a 2D shape. Rectilinear (compound) shapes A compound (or rectilinear) shape is made up of two or more basic shapes.

This shape is made up of two rectangles.

You can find the area of this shape by simply counting the squares.

The area is 10cm2.

Remember that area is always in ‘square’ units. What is the area of this shape? What is the area of this shape? How can we draw a rectangle with the given area of 30cm2? You need to remember that the formula for calculating the area of a regular shape is:

l x w

Is there more than one way to draw a rectangle with an area of 30cm2? Draw another with the same area. Hint: think about the factors of 30! What can you tell me about the area of these shapes? Calculate the area of the shape:

Part A Split the compound shape into 2 regular shapes.

Use the formula 푙 푥 푤 = 푎 and substitute in the known values for each shape.

Part A = 1 x 3 = 3

Part B = Part B 4 x (3 + 1) = 16

Add part A and part B together 3 + 16 = 19cm2 Calculate the area of the kitchen. The answer is shown on the next slide! Calculate the area of the shape.

Split the compound shape into 2 regular shapes.

Use the formula 푙 푥 푤 = 푎 and substitute in the known Part A values for each shape.

Part A = I have had to subtract 2 from 6 because Part A is no longer the full 5 x (6 – 2) = 20 length of the shape that I’m dealing with. Part B Part B = 2 x 13= 26

Add part A and part B together:

20 + 26 = 46cm2 Now, please have a go at The White Rose activity to practise finding the area of compound shapes!

You can find a PDF printable copy on the blog. There is also a screenshot of the activities on the two next two slides. The answers can be found in slides 14-15.

Answers!