Unit 7, Lesson 20-- Using Perimeter to Find Missing Side Lengths
Lesson 20-- Using Perimeter to Find Missing Side Lengths
Introduction
Hello Mathematicians! Today we will discuss how to find the perimeter of a shape when one or more side lengths are unknown.
Video
Interactive
Part 1 Directions:
- Use the square geoboard below to complete the following challenges. Record them in your math notebook.
- For example, if the challenge is "create a shape that has a perimeter of 14 units", you might create this shape, with side lengths of 5, 5, 2, and 2. You would draw this rectangle in your journal, and label the lengths of each side, along with the perimeter.
- For example, if the challenge is "create a shape that has a perimeter of 14 units", you might create this shape, with side lengths of 5, 5, 2, and 2. You would draw this rectangle in your journal, and label the lengths of each side, along with the perimeter.
Geoboard Challenges:
- Create a shape that has 4 sides with equal lengths.
- Create a shape that has a perimeter of 16 units and at least one side that is 4 units.
- Create a shape that has a perimeter of 20, and at least one side with a length of 6 units.
- Create a shape with 3 sides with a perimeter of less than 10 units.
Part 2 Directions:
- Determine the missing side lengths of the shapes below. Then, find the perimeter.
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.
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R (Read the problem carefully.) A rectangular sandbox has an area of 36 square yards. What might be the perimeter of the sandbox? D (Draw a picture.) W (Write and solve an equation.) |
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Georgia Department of Education, Math