Objective : Calculate the Objective : Calculate the area of regular area of regular quadrilaterals.quadrilaterals.

o Area is the space inside a 2D Area is the space inside a 2D shape.shape.o A quadrilateral is a 4 sided shape A quadrilateral is a 4 sided shape such as a square or a rectangle.such as a square or a rectangle.

What is area measured in?What is area measured in?

Area is measured in SQUARE Area is measured in SQUARE CENTIMETRES.CENTIMETRES.

A square centimetre is a square in A square centimetre is a square in which all the sides measure 1 cm.which all the sides measure 1 cm.

Area is also measured in SQUARE Area is also measured in SQUARE METRES.METRES.

A square metre is a square in which A square metre is a square in which all the sides measure 1 metre.all the sides measure 1 metre.

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 to Multiply the length X width to

calculate the area!calculate the area!

Example:-Example:-

10 cm

5 cm

10 cm X 5 cm = 50 square centimetres = Area

How do we write units of How do we write units of measurement for area?measurement for area?

50 square centimetres would be 50 square centimetres would be written aswritten as 50cm50cm22

32 square metres would be written 32 square metres would be written asas

32m32m22

When do you use sq.cm or When do you use sq.cm or sq.m?sq.m?

Which unit of measurement would Which unit of measurement would you use to measure these areas?you use 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?

But what if you want to But what if you want to calculate the area of an calculate the area of an irregular shape?irregular shape? What if the shape has more than 4 What if the shape has more than 4

sides?sides? How can you doHow can you do

Length X WidthLength X Width

when there isn’t a length and there isn’t when there isn’t a length and there isn’t a width?a width?

YOU HAVE TO MAKE YOU HAVE TO MAKE RECTANGLES!RECTANGLES!

Look at this shape. How could you Look at this shape. How could you calculate the area?calculate the area?

10cm

6cm

6cm

4cm

You have to create more than You have to create more than one rectangle.one 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

AB

So to calculate the area of an So to calculate the area of an irregular shapeirregular shape

Split the shape into at least Split the shape into at least two regular quadrilaterals.two regular quadrilaterals.

Calculate the area of each one.Calculate the area of each one. Add the two together.Add the two together. You’re You’re

done!!!!!!!!!!!!!!!!!!!!!!!!!!!done!!!!!!!!!!!!!!!!!!!!!!!!!!!