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• [email protected]• EGYPT – Asyut• UAE – Abu Dhabi
• 2010-2011