What is area?

What is area?

The amount of space that a figure encloses

The number of square units that covers a shape or figure.

It is two-dimensional It is always answered in square units

S is the side Area= side x side A= s x s

Find the area of a square using the formula

To find the area of a square, multiply the side x side

Area = side x side Area = 3 m x 3 m The area is 9 m2

3 m

3 m

Area of a rectangle

b is the base h is the height Area= base x height A= b x h You may also see

this as A = l x w (Area = length x width)

Find the area of the rectangle using the formula

To find the area of a rectangle, multiply the length x width.

Area= length x width The length= 6 m The width=2 m Area=6 x 2 The area is 12 m2

6 m

2 m

Area of a triangle

B is the base H is the height Area= ½ x base x

height A= ½ x b x h

Find the area of the triangle using the formulaArea = 1/2 x base x heightA= 1/2 x b x h

8 m

5 m

A= 1/2 x 8 x 5m

A= 1/2 x 40 square metersA= 20 square meters

The area is 20 m2

Area of a parallelogram

b is the base h is the height Area= base x height A= b x h

Find the area of parallelogram using the formula

Area = base x height

A= b x h

A= 4 x 3

A= 12 square units The area is 12 units2

What is the area of this figure?

It is a square Formula for the area of

a square is side x side Side= 17 m Area= 17 x 17 A= 289 m2

17 m.

17 m


It is a triangle

13 cm

4 cmFormula for the area of a triangle is A = ½ x base x heightBase= 13 cmSide= 4 cm

Area= ½ x 13 x 4 A= 26 cm2


It is a parallelogram

Formula for the area of a parallelogram is

A = base x height

Base= 3 units

Height= 6 units

Area= 6 x 3

A= 18 units2


It is a rectangle Formula for the area of

a rectangle is length x width

Length= 8m Width= 3 m Area= 8 x 3 A=24 m2

3 m

8 m


It is a square Formula for the area of

a square is side x side Side= 12 cm Area= 12 x 12 A= 144cm2

12 cm

12 cm


It is a triangle Formula for the area of

a triangle is ½ x base x height

Base= 8 m Side= 5 m Area= ½ x 8m x 5 m A=20 m2

8 m

5 m


It is a parallelogram

Formula for the area of a parallelogram is A = base x heightBase= 5 unitsHeight= 5 units

Area= 5 x 5 A= 25 units2


It is a rectangle

Formula for the area of a rectangle is

A = length x width

Length= 13 cm

Width= 4 cm

Area= 13 x 4

A= 52 cm2

13 cm

4 cm


It is a rectangle 7 cm

16 cm

Formula for the area of a rectangle is A = length x width

Length= 16 cmWidth= 7 cm

Area= 16 x 7 A= 112 cm2

Do you remember the formula for the area of a circle?

For a circle, the area is:

A = Πr2

= Π x 52

=78.54 cm2

What about unusual / composite shapes?This shape can be divided into

two rectangles. Find their areas and add them together.

Area 1= l x b= 8 x 20

= 160 cm2

Area 2= l x b= 4 x 6

= 24 cm2

Total area = A1 + A2= 160 + 24=184 cm2

Try another one:In this case, a

measurement needs to be found before you begin.

7 m

A1 = 5 x 8 =40cm2

A2 = 15 x 7

=105 cm2

Total area = A1 + A2= 40 + 105= 145 cm2

What did you learn?

What is area? How are the units of area usually expressed? How many dimensions is area? What does the “S” mean in the formula for the area of

a square? What is the formula for the area of a square? What is the formula for the area of a rectangle? What does the “h” stand for in the formula for the

area of a triangle?

More…

What is the formula for the area of a parallelogram? What does the “b” stand for in the formula for the

area of a triangle? What does the “h” stand for in the formula for the

area of a rectangle? What is the formula for the area of a rectangle? What are the four formulas we have learned today?

Closure: Remember Formulas!

Square: A = s x s Rectangle : A = b x h Triangle: A = ½ x b x h Parallelogram: A= b x h Circle: A = π x r2

http://www.ideal-resources.com.au/products/secondary_maths_pack/Class/wc3.swf

http://www.ideal-resources.com.au/products/secondary_maths_pack/Class/wc2.swf

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What is area?