Unit 7, Lesson 13-- Using Area to Find Missing Side Lengths

Lesson 13-- Using Area to Find Missing Side Lengths

Introduction

Hello Mathematicians! Today we will use what we know about area to find missing side lengths of rectangles.

Think about the following question:

If the area of a rectangle is 16 square inches, what could the side lengths be? In your notebook, explain how you know. 

Use the tiles to help you.

Video

Interactive

Directions:

  • Use what you know about multiplication and division to answer the following questions.  Remember: Area = Length X Width
  • Show your answer in your notebook using drawings, numbers, and words.
    • 1. If the area of a rectangle is 16 square inches, what could the side lengths be? Explain how you know. 
    • 2. If a square has an area of 24 square feet, what is the length of each side?
    • 3.  If a rectangle has a side length of 4 and an area of 28 square feet, what is the length of the missing side? Write an equation and solve the problem.

In Your Math Notebook:

Let’s get out our math journals and  work through the following application problem. Make sure you read the problem carefully, draw a picture to match your thinking and write and solve an equation.

Read, Draw, Write. DONE!

R (Read the problem carefully.)

My dog Finley has a square pen in the backyard. One of the side lengths is 10 feet. What is the total area of the pen? Explain your thinking with pictures, numbers, and words.

D (Draw a picture.)

W (Write and solve an equation.)

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Georgia Department of Education, Math