1. Area of Shapes The area of a shape is the space it occupies.
Write down the name of each shape.
A powerpoint presentation by
Carmelo Ellul
Head of Department (Mathematics)
Parallelogram
Trapezium
Square
Rectangle
Circle
Triangle

2. Area of Shapes Click button to select topic. Square Rectangle
Parallelogram
Triangle
Trapezium
Circle
End Show

3. The Square Area = l x b e.g. Find the area of a square of side 3.5 cm.
Discuss
and work out
this example
together
with your friend.
breadth b
A = l x b
A = 3.5 cm x 3.5 cm
= cm2 l
length

4. The Rectangle Area = l x b e.g. Find the area of a rectangle of
length 3.5 cm and height 80 mm.
Discuss
and work out
this example
together.
Since units must be the same:
10 mm = 1 cm
80 mm = 80 mm ÷ 10 = 8 cm
A = l x b
A = 3.5 cm x 8 cm
= 28 cm2 b l

5. The Parallellogram Area = b x h e.g. Find the area of a parallelogram
correct to 1 d.p.
3.8 cm
10.3 cm h
height
base b
Discuss
and work out
this example
together.
A = b x h
A = 10.3 cm x 3.8 cm
= cm2
= 39.1 cm2 b h

6. The Triangle Area = ½ b h e.g. Find the area of triangle ABC
correct to the nearest cm2.
11.7 cm
4 cm A B C
height h b
base
Area of = ½b  h b h
Area of = ½ area of parallelogram b h
A = ½b x h
A = ½ x 4 cm x 11.7 cm
= cm2
= 23 cm2
Area of parallelogram = b  h b h
Discuss
and work out
this example
together.

7. Decide about the values
The Trapezium
Area = ½h(a + b)
e.g. Find the area of the trapezium.
Length of side a a
12 cm
8.5 cm
6 cm h
height
Length of side b b
h = 6cm, a = 8.5 cm, b = 12 cm
A = ½h(a + b)
A = ½ x 6 cm x (8.5 cm + 12 cm)
= ½ x 6 cm x 20.5 cm
= 61.5 cm2
Decide about the values
of a, b and h
to find the area. a b h
Rotate the trapezium b a
Area of 1 trapezium is half h(a + b)
 Area of trapezium = ½ h(a + b)
The 2 trapeziums form a parallelogram
Area of parallelogram = h(a + b)
Copy the trapezium

8. The Circle Area = p r2 = p x 9.5 cm x 9.5 cm
e.g. The diameter of a circle is 19 cm. Find, correct to nearest whole
number, the area of a circle.
Radius r
Find the radius first
and then work out
this example
together.
r = 19 cm ÷ 2
= 9.5 cm.
A = p r2
= p x 9.5 cm x 9.5 cm
= cm2
= 284 cm2
Centre
Remember:
the radius
of a circle is
half the diameter.

9. The Circle Area = p r2 = p x 9.5 cm x 9.5 cm
e.g. The diameter of a circle is 19 cm. Find, correct to nearest whole
number, the area of a circle. r
r = 19 cm ÷ 2
= 9.5 cm.
A = p r2
= p x 9.5 cm x 9.5 cm
= cm2
= 284 cm2
Remember:
the radius
of a circle is
half the diameter.
End Show