Perimeter and Area
First we need to find the length of each side by counting the squares 8 cm
6 cm
6 cm
The distance around the outside of a shape is called the perimeter.
8 cm
The perimeter of the shape is 8 + 6 + 8 + 6 = 28cm.
18cm
18cm
What is the perimeter of each of these shapes?
22cm 18cm
26cm
Now find the perimeter of these shapes. They are not drawn to scale.
5cm
3cm 3cm
4cm
3cm
7cm 3cm
7cm
3cm 3cm
Perimeter = 18cm
4cm
3cm
3cm
3cm
3cm
4cm
4cm
3cm Perimeter = 22cm
Perimeter = 28cm
To find out how much shape is inside we can count the squares.
The area of a shape is the amount of space inside it.
The area of the shape is 18cm2.
12cm2
What is the area of each of these shapes?
26cm2
26cm2
This is an irregular shape. This means that the sides are not straight.
To find the area of an irregular shape you first count the full squares inside it.
You then count all the other squares which have more than half the area covered. The area of the shape is 60cm2.
24cm2
25cm2
What is the area of each of these shapes?
35cm2
22cm2
The rectangle is made of 6 rows of 8 squares. To work out the number of squares we times 6 by 8. Counting each square can take a long time. Does anyone know a quicker way?
The area of the shape is 48cm2.
18cm2
2
20cm
What is the area of each of these shapes?
2
30cm 14cm2
22cm2
We can work out the area of a rectangle without the grid. length
width
Area = length x width
Now work out the area of these rectangles. They are not drawn to scale. 7cm
9cm
2
35cm2
36cm
5cm 20cm2
5cm
12.5cm
4cm 2cm
25cm2
4cm
Total area = 40 + 32 = 72 cm2
4cm 2cm
10cm
4cm
Area = 4 x 10
Area = 4x8
2
40cm
32cm2
8cm
A shape that is made from other shapes is known as a composite shape.
8cm
To find the area of this shape we have to split it up into two rectangles.
5cm 2cm 4cm 9cm
5cm
2cm
4cm 2cm 11cm 5cm 4cm
3cm 3cm
Find the area and perimeter of each of these shapes? Your teacher will give you copy of the worksheet.
5cm 4cm
3cm
6cm
4cm 7cm
7cm 6cm 11cm
5cm 2cm
9cm
Area = 5x9 45cm
Area = 4x5
4cm 5cm
2
20cm2
4cm 2cm 5cm
Total area = 45 + 20 = 65 cm Perimeter = 36 cm
2
2
Total area = 10 + 36 = 46 cm Perimeter = 34 cm
2cm
Area = 2x5
10cm2
11cm
5cm 4cm
Area = 6x6 36cm2 6cm
6cm
Total area = 28 + 16 + 21 = 65 cm
2
Perimeter = 42 cm Area = 4x7 28cm2
Area = 4x4 2 16cm
4cm
3cm 3cm
3cm
4cm 7cm
7cm
11cm
There is another way of doing this question. Area = 3x7 21cm2
2
Total area = 77 – 12 = 65 cm
Perimeter = 42 cm Area = 3 x 4 12cm2 4cm
3cm 3cm
3cm
4cm 7cm
7cm
Area = 7 x 11
77cm2 11cm
w o r k s h e e t o n e
w o r k s h e e t t w o
w o r k s h e e t t h r e e
5cm 2cm 2cm
4cm 9cm
5cm
5cm
4cm 11cm
2cm
4cm
5cm
6cm
4cm
3cm
3cm 7cm
4cm
11cm
6cm
3cm 7cm
w o r k s h e e t f o u r
Review
Name:____________________
What is the area of the moon? _____________________cm2
What is the area of the rectangle? _____________________cm2 What is the perimeter of the rectangle? _____________________cm
What is the area of the house? _____________________cm2
4cm
8cm
4cm
What is the area of the compound shape?
2cm
_____________________cm2 4cm
What is the perimeter of the compound shape? _____________________cm
6cm