The document discusses calculating the area of rectangles and irregular shapes. It explains that area is measured in square units like square centimeters and square meters. To find the area of a rectangle, you multiply its length by its width. For irregular shapes, you split the shape into multiple rectangles, calculate the area of each, and add them together to find the total area.

1. Objective : Calculate the areaObjective : Calculate the area
of rectangles.of rectangles.
o Area is the space inside a 2D shape.Area is the space inside a 2D shape.
o Squares and oblongs are bothSquares and oblongs are both
rectangles.rectangles.

2. What is area measured in?What is area measured in?
 Area is measured in SQUAREArea is measured in SQUARE
CENTIMETRES.CENTIMETRES.
 A square centimetre is a square in whichA square centimetre is a square in which
all the sides measure 1 cm.all the sides measure 1 cm.
 Area is also measured in SQUAREArea is also measured in SQUARE
METRES.METRES.
 A square metre is a square in which all theA square metre is a square in which all the
sides measure 1 metre.sides measure 1 metre.

3. How do we calculate area?How do we calculate area?
 It’s really easy!It’s really easy!
 Measure the length.Measure the length.
 Measure the width.Measure the width.
 Multiply the length X width toMultiply the length X width to
calculate the area!calculate the area!

4. Example:-Example:-
10 cm
5 cm
10 cm X 5 cm = 50 square centimetres = Area

5. How do we write units ofHow do we write units of
measurement for area?measurement for area?
 50 square centimetres would be written as50 square centimetres would be written as
50cm50cm22
 32 square metres would be written as32 square metres would be written as
32m32m22

6. When do you use cmWhen do you use cm22
or mor m22
??
 Which unit of measurement would you useWhich unit of measurement would you use
to measure these areas?to measure these areas?
 Area of a floppy disk?Area of a floppy disk?
 Area of a CD cover?Area of a CD cover?
 Area of a table?Area of a table?
 Area of a netball court?Area of a netball court?

7. But what if you want to calculateBut what if you want to calculate
the area of an irregular shape?the area of an irregular shape?
 What if the shape has more than 4 sides?What if the shape has more than 4 sides?
 How can you doHow can you do
Length X WidthLength X Width
when there isn’t a length and there isn’t awhen there isn’t a length and there isn’t a
width?width?

8. YOU HAVE TO MAKEYOU HAVE TO MAKE
RECTANGLES!RECTANGLES!
 Look at this shape. How could youLook at this shape. How could you
calculate the area?calculate the area?
10cm
6cm
6cm
4cm

9. You have to create more than oneYou have to create more than one
rectangle.rectangle.
 Like this!Like this!
10cm
6cm
6cm
4cm
4cm
A = 6cm X 4cm = 24cm2
B = 6cm X 4cm = 24cm2
A + B = Area
24cm2
+ 24cm2
= 48cm2
A
B

10. So to calculate the area of anSo to calculate the area of an
irregular shapeirregular shape
 Split the shape into at least twoSplit the shape into at least two
rectangles.rectangles.
 Calculate the area of each one.Calculate the area of each one.
 Add the two together.Add the two together.
 You’re done!You’re done!