Loading...

PPT – Area of a rectangle PowerPoint presentation | free to download - id: 5fedd4-MGNhY

The Adobe Flash plugin is needed to view this content

Simple Areas

Area of a rectangle

Area of a right-angled triangle

www.mathsrevision.com

Area of a circle

Area of composite shapes

Starter Questions

www.mathsrevision.com

34o

Area of a Rectangle

Learning Intention

Success Criteria

- To be able to state area formula for a rectangle.

1. To come up with a formula for the

area of a rectangle.

- Apply formula correctly.
- (showing working)

www.mathsrevision.com

- Use the formula to solve problems.

- Answer containing
- appropriate units

Problem

www.mathsrevision.com

Only 5 a square metre!

How much for this one?

?

Problem

1m

1m

1 square metre

6 m

6 square metres

6 square metres

3 m

6 square metres

www.mathsrevision.com

3 rows of 6 squares

3 x 6

18 square metres

18 x 5 90

How much for 18 square metres?

Area of a rectangle

6

6 m

length

3

3 m

breadth

www.mathsrevision.com

6

x 3

18 m²

Area

length

x breadth

Area

Now try TJ Int 1 Chapter Ex Page

www.mathsrevision.com

Example 1

Area length x breadth

A l x b

11 cm

A 11 x 6

6 cm

A 66 cm²

www.mathsrevision.com

Find the area of the rectangle

Example 2

Area length x breadth

A l x b

A 12 x 12

A 144 cm²

www.mathsrevision.com

12 cm

Find the area of the square

Starter Questions

www.mathsrevision.com

123o

Area of A Right-Angled Triangle

Learning Intention

Success Criteria

- Know area of a right-angled triangle formula

1. Use the area of a rectangle formula to help

us to come up with a formula to calculate the

area of any right-angled triangle.

2. Use formula to work out area of triangle.

www.mathsrevision.com

3. Show all working and units.

Area of a right-angled triangle

4 cm

7 cm

www.mathsrevision.com

Area of rectangle

l x b

28 cm²

7 x 4

Area of triangle

½ x Area of rectangle

½ x 28

14 cm²

Area of triangle Short cut

4 cm

height

base

7 cm

www.mathsrevision.com

Area of triangle

½ x 7 x 4

14 cm²

½ x 28

Area ?

x base

x height

½

Example 1

Area ?½ x base x height

A? ½ x b x h

A? ½ x 15 x 10

10 cm

A? 75 cm²

www.mathsrevision.com

15 cm

Find the area of the triangle

Example 2

Area ?½ x base x height

8 cm

A? ½ x b x h

A? ½ x 8 x 12

12 cm

A? 48 cm²

www.mathsrevision.com

Find the area of the triangle

Area

Now try TJ Int 1 Chapter Ex Page

www.mathsrevision.com

Starter Questions

www.mathsrevision.com

123o

Area of circle

Learning Intention

Success Criteria

- Know area of a circle formula

1. Use the area of a circle formula to

calculate the area of different size circles,

semi-circles and quarter circles.

2. Use formula to work out area of different size

circles, semi-circles and quarter circles.

www.mathsrevision.com

3. Show all working and units.

Area of a circle

Q. Find the area of the circle ?

10cm

www.mathsrevision.com

The Area of a circle

Q. Find the area of the circle ?

4cm

www.mathsrevision.com

The Area of a circle

- The diameter of the circle is 60cm.
- Find area of the circle?

www.mathsrevision.com

The Area of a circle

Find the area of the semi-circle ?

Solution

www.mathsrevision.com

length of the arc of a circle

Find the area of the quarter circle ?

8cm

www.mathsrevision.com

Composite shapes

Now try TJ Int 1 Chapter Ex Page

www.mathsrevision.com

Starter Questions

www.mathsrevision.com

Area of a Composite

Made up of Simple shapes

Learning Intention

Success Criteria

- To be able to use knowledge gained so far to find

the area of more complicated shapes..

1. To use knowledge to find area of more

complicate shapes.

www.mathsrevision.com

- Show appropriate working.

Composite shapes

10 cm

6 cm

?

3 cm

www.mathsrevision.com

Composite shapes

10 cm

6 cm

(1)

6 cm

(2)

?

3 cm

www.mathsrevision.com

Area (1)

l x b

60 cm²

10 x 6

Area (2)

½ x b x h

½ x 3 x 6

9 cm²

Area of shape

(1) (2)

69 cm²

60 9

Example

l x b

Area (1)

15 x 8

120 cm²

?

8cm

(1)

Area (2) l x b

9 x 3

27 cm²

(2)

(1) (2)

Area of shape

120 27

9cm

147 cm²

Find the area of the shape

Example

l x b

Area (1)

20 x 12

240 cm²

Area (2) l x b

10 x 6

(2)

60 cm²

(1) (2)

Area of shape

240 -60

(1)

180 cm²

Find the area of the shape

Mixed Problems

Example Find the area of the shape

Area rectangle semicircle

www.mathsrevision.com

Mixed Problems

The Circle

Example A circle is contained in a

square. Find the grey shaded area below.

8cm

Area square - circle

www.mathsrevision.com

Composite shapes

Now try TJ Int 1 Chapter Ex Page

www.mathsrevision.com