Area and Perimeter of Composite

figures

After completing activities

• Review the formulas for Perimeter and Area of basic shapes on the next slides

• View the animated worked example on the following slides

Formulas for basic Quadrilaterals

Formulas for basic Quadrilaterals

Formulas for basic Quadrilaterals

Example 1Find the area of the figure below

15 cm

50 cm

15 cm

= + +

50 cm

Triangle Rectangle

Square 20cm 15 cm15 cm 3

0 c

m

30 c

m

Area = Height × base 2

Area = 30 × 20

Area =

Rectangle:

Area = Length × width

Area = 30 × 15

Area =

Square :

Area = (side)2

Area = (15)2

Area = 300 cm2 450 cm2 225 cm2

2

Triangle :

Total area = 300 + 450 + 225

= 975 cm2

What is the area of the window shown? Use ( π =3.14 )

Example 2

48 in

36 in

48 in

36 in

+36 in

36 in4

8 in

=

48 in

36 in

=+

36 in

36 in

48

in

Rectangle :Area = 36 × 48 Area = 1728 in2

Half of circle :Area =

Area = 508.68 in2

𝜋𝑟2 23.14 × (18)2 2Area =

508.68 in21728 in2

Total area = 1728 + 508.68

= 2236.68 in2

8cm

6cm

8cm

12cm

Example 3

8cm

6cm

8cm

12cm

+

4cm

4cm

-

8cm

6cm

8cm

12cm

+4cm

4cm-

bhA

2

442

bh

A

Total Area = 96 + 40 – 8 = 128 cm2

2

21

40

)46(82

1

)(2

1

cm

bbhA

4cm

128A

A = 8 cm2A = 96 cm2

Thank you• Mr. Ali Abdalla Abdelmohsen Mahmoud• alielbasry2@yahoo.com• EGYPT – Asyut• UAE – Abu Dhabi

• 2010-2011