Page 140 - Math Course 1 (Book 2)

Geometric Area: Composite Figures

Mo. 10

Lesson 7 Postulate 10.2

The area of a region is the sum of the areas of all
its non overlapping parts.
KEY CONCEPTS:
1. Find areas of composite f gures.
2. Find areas of composite f gures on the Let’s Begin
coordinate plane.

MO. 10 - L7a Area of a Composite Figure

Finding Areas of Composite Example

Figures
What is the area of the composite f gure? Round to
Vocabulary A-Z the nearest tenth.
Let us learn some vocabulary A 713.1 ft 2 32 ft
B 852.5 ft 2
C 953.1 ft 2 16 ft
D 992 ft 2
composite f gure
A composite f gure is a f gure that can be 15 ft
separated into regions that are basic f gures.

A Read the Test Item
The f gure can be separated into a rectangle with
dimensions 16 feet by 32 feet, a triangle with a
base of 32 feet and a height of 15 feet, and two
semicircles with radii of 8 feet.
D
E
Solve the Test Item
Area of composite f gure

= area of rectangle + area of triangle + area of 2
semicircles.
1 1 Area
2
= bh + bh + 2( πr )
1 2 2 2 formulas
1
1
2
= (16)(32) + (32)(15) + 2[ π(8) ] Substitution
2 2
C F B
= 512 + 240 + 64π Simplify.
Use a
= 953.1
calculator.
The area of the composite f gure
is 953.1 square feet to the
Answer
nearest tenth. The correct
answer is C.

132