Perimeter and Area
Perimeter:
The total distance around the outside of a shape.
(The length of its outline)
Measured in units of length (mm,cm,m,km)
Area:
The space a shape takes up.
Measured in units of area ( mm², cm², m²)
The area of a rectangle is length x breadth
Breadth
Length
Notice the area of a square is a special case because all sides are equal
so length = breadth
The area of a triangle is base x height
Height
Base
Remember: There must be a right angle between the base and the
height.
The area of a composite shape can be found by breaking the shape
into its more simple components and finding the area of each.
1.
Calculate the area and the perimeter of each rectangle below :
8cm
(b)
(a)
5cm
7cm
(e)
14mm
(d)
6mm
5m
(c)
9cm
1.8m
2m
3.8cm
(f)
3.2cm
5m
2. Calculate the shaded area in each diagram below :
0.8m
9cm
4cm
6mm
2cm
15mm
2.4m
5cm
2m
13mm
(a)
(b)
(c)
22mm
0.4m
3. Calculate the area of each composite shape below :
(a)
(b)
6cm
3m
(c)
2.4m
24cm
5cm
4cm
3cm
14cm
9cm
2.4m
14cm
0.8m
Answers
1.
a)
c)
e)
A = 40 cm2, P = 26 cm
A = 10 m2, P = 14 m
A = 9 m2, P = 13.6 m
2. a)
A = 26 cm2 b)
3. a)
A = 72 cm2 b) A = 222 cm2
b)
d)
f)
A = 252 mm2 c)
A = 63 cm2, P = 32 cm
A = 84 mm2, P = 40 mm
A= 12.16 cm2, P = 14 cm
A = 1.12 m2
c) A = 9.12 m2