### Geometry Area of Composite Figures-1

```Take out a calculator to
try to solve the following
problems on area of
composite figures.
For Learning to Happen!
•Pay close attention to this lesson.
•This lesson is very short.
•However, this is a challenging lesson!
•It is important to follow along with the slides
so that you know how to do you know how to
calculate the area of composite figures!
To understand
COMPOSITE FIGURES
you first must know
how to calculate
missing sides.
What are the missing side lengths?
12 m – 9 m =
3m
9m
6m
3m
12 m
What are the missing side lengths?
6m –3m=
3m
3m
6m
9m
3m
12 m
What are the missing side lengths?
3 ft
10 ft – 7 ft = 3 ft
7 ft
10 ft
What are the missing side lengths?
1 in
5 in + 3 in + 2 in + 1 in = 11 in
2 in
14 in – 11 in =
3 in
3 in
5 in
14 in
There are multiple
methods for solving Area
of Composite Figures.
st
The 1 method I am
going to show you is
how to break it up into
simpler area problems.
What is the total shaded area?
Area1 A  s
2
3  9
3m
6m
2
3m
9m
12 m

3 m Area 2 A  bh
 12  3
Total Area
 36

45 m
2
nd
2
The
method involves
finding an entire area
and then subtracting
smaller areas.
Pay attention you don’t
want to miss this!
What is the total shaded area?
3m
Area1
3m
6m
9m
12 m

= l·w
6  12  72 m2
3 m Area 2 = l · w
2
9  3  27 m
=
Total Area
 45 m2
Find the perimeter of the figure below.
10
8
Perimeter
4
4
8
6
8 +16 +8 +10 +4 +6 +4
= 56 UNITS
16
16 – 6 = 10
Find the area of the figure below.
Area
10
Area1  l  w
4
8
4
6
16
8
-
16 · 8 = 128 un
Area 2  l  w
=
Total
Area
6 · 4 = 24 un
2
2
= 104 un
2
Find the area of the figure below.
12- 5 = 7ft
Subtract the area of the
triangle from the area of
the rectangle.
Area of the rectangle:
A = bh
A = 12
•
9=
108
9 ft
5 ft
6 ft
12 ft
Area of the triangle:
1
__
A = bh
2
1
ft2 A = __
• (6)(7)
2
1
__
A=
• 42 =
2
21 ft2
Find the area of the figure below.
12- 5 = 7ft
Area of the rectangle
– Area of the triangle
A=
9 ft
108 – 21 = 87 ft2
Area of the rectangle:
A = bh
A = 12
•
9=
108
5 ft
6 ft
12 ft
Area of the triangle:
1
__
A = bh
2
1
ft2 A = __
• (6)(7)
2
1
__
A=
• 42 =
2
21 ft2
THE END!!!
#10
Area
20 m
13 m
5m
12 m
25m
Perimeter
Area1 = l · w
2
20  12  240 m
+
b

h
Area 2  2
5  12  30 m2
P = 12 + 20 + 13 + 25
2
2
P = 70 m
Total Area
 270 m
=
ANOTHER WAY: Area of a Trapezoid
A = (b1 + b2) x h
2
12(25  20)

2