1. Area of composite figures
Objective: to be able to find area of composite figures and use that process to solve real life problems.

2. Let’s review formulas for area
7 ft
Square/
Rectangle
L • W
4 ft
28 ft2
9 cm
81 cm2

3. Let’s review formulas for area
Triangle
½ b • h
5 ft
4 ft
10 ft2

4. Let’s review formulas for area
Circle
3.14 • r2
6 in
in2

5. Let’s Practice!
9.2 m
7.25 m
4.3 m
3 m
19.78 m2
21.75 m2

6. Let’s Practice!
15 m
5 cm
cm2
225 m2

7. Way to go!

8. Let’s look at some new formulas for area
Parallelogram
b • h
4 ft
5 ft
7 ft
35 ft2

9. Let’s practice the new formula for area
Parallelogram
b • h
4 ft
6 ft
12 ft
72 ft2

10. Let’s practice the new formula for area
Parallelogram
b • h
3.5 in
2.5 in
8 in
28.0 in2

11. Let’s look at another new formula for area
Trapezoid
Just a reminder…name the only characteristic that trapezoids have.
1 set of parallel sides

12. Let’s look at another new formula for area
Trapezoid ½ h(b1 + b2)
4 in
2 in
7 in
11 in2

13. Let’s practice the new formula for area
Trapezoid ½ h(b1 + b2)
10 in
6 in
4 in
32 in2

14. Let’s practice the new formula for area
Trapezoid ½ h(b1 + b2)
23 in
9 in
17 in
180 in2

15. Let’s practice!

16. Let’s look at composite figures now!
Composite Figures are made up of two or more shapes.
To find the area of a composite figure, you must decompose the figure into shapes with areas that you know and then find the sum of these areas!

17. Find the area of the composite figure.
Example 1
Find the area of the composite figure.
The area can be separated into a semicircle and a triangle.
½ (3.14)(r2) for circle
½ (b)(h) for triangle
6 m
11 m
14.1 m +
33 m =
47.1 m2

18. Find the area of the composite figure.
Example 1
20 m
Find the area of the composite figure.
The area can be separated into a trapezoid and a rectangle.
½ h (b1 + b2) for trapezoid
L • W for square
20 m
13 m
25 m
82.5 m +
400 m =
482.5 m2

19. Awesome work!

20. Let’s try word problems
Pedro’s father is building a shed. How many square feet of wood is needed to build the back of the shed shown at the right?
4 ft
12 ft
15 ft
210 ft2

21. What about shaded areas?
Find the area of each shape and subtract.
3 cm
7 cm
4 cm
13 cm
79 cm2

22. Let’s practice!