Obj. 46 Composite Figures

The student is able to (I can):

• Find the area of composite figures

composite figure

A shape made up of simple shapes such as triangles, rectangles, trapezoids, and circles.

To find the area of the composite figure, divide the shape into the simple shapes, find the areas of each, and add (or subtract) them.

Examples Find the area of each shape. Round to the nearest tenth if necessary.

1.38

20

70

40

760

3238− =

2 240 32 24

24

( )( ) =132 24 384

2

384

Area = 760 + 384 = 1144

(20)(38) = 760

Examples 2.

17" 42"

8"

Area = Triangle — ½ Circle

= =1

Triangle (17)(42) 357 sq. in.2

= π = π211 Circle (4 ) 8 sq. in.2 2

= − π ≈A 357 8 331.9 sq. in.

Examples 3. Find the area of the shaded portion to the nearest tenth.

6 ft.

( )= π = π2 2Circle 3 9 ft

( )( )= =21

Square 6 6 18 ft2

= π − ≈2Area 9 18 10.3 ft