Lesson 10 Problem Solving With Perimeter and Area

- Let’s solve problems involving perimeter and area.

Warm-up True or False: Divide in Parts

Decide if each statement is true or false. Be prepared to explain your reasoning.

$60 \div 6 = 10$
$72 \div 6 = (60 \div 6) + (12 \div 6)$
$78 \div 6 = (60 \div 10) + (18 \div 6)$
$96 \div 8 = (80 \div 8) - (16 \div 8)$

Activity 1 Rope Off the Garden

Andre wants to know how much rope is needed to enclose the new rectangular school garden. The length of the garden is 30 feet. The width of the garden is 8 feet.

Clare says she can use multiplication to find the length of rope Andre needs.
Diego says he can use addition to find the length of rope Andre needs.

Who do you agree with? Explain or show your reasoning.

Activity 2 Info Gap: A Garden and a Playground

Your teacher will give you either a problem card or a data card. Do not show or read your card to your partner.

Information Gap routine directions for problem card student and data card student.

Pause here so your teacher can review your work.

Ask your teacher for a new set of cards and repeat the activity, trading roles with your partner.

Practice Problem

Problem 1

A rectangular card has an area of 60 square centimeters. It is 4 centimeters longer than it is wide. What is the perimeter of the card? Explain or show your reasoning.