Area of Shapes

1
Area of Shapes

• The area of a shape is the space it occupies.
• Write down the name of each shape.

Parallelogram
Trapezoid
Square
Rectangle
Circle
Triangle
2
Area of Shapes

• Click button to select topic.

Square
Rectangle
Parallelogram
Triangle
Trapezoid
Circle
End Show
3
The Square

• Area l x l

e.g. Find the area of a square whose side
is 3.5 cm.
Discuss and work out this example together
with your friend.
l
A l x l A 3.5 cm x 3.5 cm 12.25 cm2
l
length
4
The Rectangle

• Area l x w

e.g. Find the area of a rectangle that has a
length of 3.5 cm and a height of 80 cm.
Discuss and work out this example together.
Since units must be the same A l x w A 3.5
cm x 80 cm 280 cm2
w
l
5
The Parallellogram

• Area b x h

e.g. Find the area of the parallelogram
below to the tenths.
height
h
base
b
A b x h A 10.3 cm x 3.8 cm 39.14 cm2
39.1 cm2
Discuss and work out this example together.
6
The Triangle

• Area ½ b? h

e.g. Find the area of triangle ABC to the
nearest whole cm.
height
h
base
b
A ½b x h A ½ x 4 cm x 11.7 cm 23.4 cm2
23 cm2
Discuss and work out this example together.
7
The Trapezoid

• Area ½h(a b)

e.g. Find the area of the trapezoid.
Length of side a
a
h
height
Length of side b
b
Decide about the values of a, b and h to find
the area.
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
Copy the trapezium
a
b
h
The 2 trapeziums form a parallelogram
Area of 1 trapezoid is half h(a b)
Area of parallelogram h(a b)
a
b
? Area of trapezoid ½ h(a b)
8
The Circle

• Area p r2

e.g. The diameter of a circle is 19 cm. Find
the area of the circle to the nearest cm.
r 19 cm 2 9.5 cm. A p r2 p x 9.5
cm x 9.5 cm 283.5 cm2 284 cm2
Radius
r
Find the radius first and then work out this
example together.
Center
Remember the radius of a circle is half the
diameter.
9
The Circle

• Area p r2

e.g. The diameter of a circle is 19 cm. Find
the area of the circle to the nearest cm.
r 19 cm 2 9.5 cm. A p r2 p x 9.5
cm x 9.5 cm 283.5 cm2 284 cm2
r
Remember the radius of a circle is half the
diameter.
End Show