7th Grade Math

GLE 0706.1.2 Apply and adapt a variety of appropriate strategies to problem solving, including estimation,

and reasonableness of the solution. Also addresses SPI 0706.2.3.

602 Volume and Surface Area

Problem-Solving Investigation

Main Idea Solve problems by solving a simpler problem.

Solve A Simpler Problem

LIAM: For a service project, I am helping mulch

the play area at the community center. We need to

know how large the play area is in order to buy

the right amount of mulch. The diagram shows the

dimensions of the play area.

YOUR MISSION: Find the area of the play area to

be mulched.

Composite Figures

PART A BC

Understand You know that the play area is made of

two rectangles.

13 ft

7 ft

10 ft

8 ft

5 ft

Plan Find the area of the two rectangles, and

then add.

Solve Area of Rectangle 1 Area of Rectangle 2

A = ℓw A = ℓw

A = 5 · 10 A = 8 · 7

A = 50 A = 56

The total area is 50 + 56 or 106 square feet. So, we need to buy enough mulch

for at least 106 square feet.

Check The play area is less than 13 · 10 or 130 square feet. So, an answer of

106 square feet is reasonable.

1. Why is breaking this problem into simpler parts a good strategy to solve it?


2. E WRITE MATH Write a problem that can be solved when broken into
   simpler parts. Solve the problem and explain your answer.

Multi-Part

Lesson 3

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