Unit 7, Lesson 24-- Math in Our World: Building a Dog Pen

Lesson 24--  Math in Our World: Building a Dog Pen

Introduction

Hello Mathematicians! Today we will continue to use area and perimeter to solve real- world problems.

First, take a look at these images.  Find the area and perimeter of each rectangle. 

What is the same? What is different? What do you notice about the number of square units and the shape of the rectangle?  Jot down your thoughts in your math notebook.

Rectangles in arrays. 4 rows of 11. 3 rows of 12. 2 rows of 13. 1 row of 16. 8 rows of 7.

Interactive

Part 1 Directions:

  • A mail carrier rescues a homeless dog. The mail carrier has 24 feet of fencing and would like to build a pen for Arfy so that he can play in the backyard while she is at work. She wants the pen to be shaped like a rectangle. What are the possible dimensions of the pen? 
  • Use the interactive geoboard below to create your pens.  Draw them in your notebook, and label the side lengths and perimeter.
  • Which pen do you think will be the best for Arfy? Why?  Share your design on the Next page.

Part 2 Directions:

  • The mail carrier decided to build a triangular pen with a perimeter of 24 feet for Arfy. She wants each side of the pen to be the same length.
  • Use pictures, numbers, and words to describe what Arfy’s pen will look like. Label the lengths of each side.

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Georgia Department of Education, Math