Perimeter
Background Information & Activities

© 1999-2012 BrainPOP. All rights reserved.

This movie will teach when perimeter is used and how to calculate it. You may wish to screen the Inches and Feet movie to review basic measurement skills. Explain to your children that the perimeter is the total distance around something. It might be easier for some children to think of the perimeter as an outline. For example, a map shows the perimeter of states and countries, and a soccer field or basketball court has lines that show the perimeter of the playing area. Come up with more examples together..

Review with your children that we find the perimeter of a shape or figure by adding the lengths of all its sides. Find the perimeter of an object together. You may want to use a pattern block or draw a shape. Find the length of each side and then add the lengths. For example, a square with 2-inch sides has a perimeter of 2 in. + 2 in. + 2 in. + 2 in. = 8 in. To help children solve these longer number sentences, you may want to review a few strategies, such as skip-counting, counting on, adding doubles, or making ten. Check out the Addition and Subtraction unit for movies on strategies. You can also encourage children to utilize a strategy mentioned in this movie, which is adding the easier numbers first, instead of adding them in the order they appear. For example, in the number sentence 3 + 2 + 5 + 3 + 7, children can add 3 + 2 = 5 and then add 5 + 5 = 10, which is a doubles fact. Then they can easily add 10 + 7 = 17 by using the adding ten strategy. Then they can count on 3 to find the sum: 17 + 3 = 20.

Practice finding the perimeter of shapes with unequal sides and shapes that have more than four sides. You may want to have children cut shapes out of paper and exchange them with other children to measure and determine the perimeter. This is a great chance to measure in inches and also in centimeters. It is also an opportunity to explore nonstandard units and practice using measurement tools such as rulers and tape measures.

Help your children understand that knowing how to calculate perimeter will be useful in many situations, especially in designing and building. Why might it be important to know the perimeter of a yard or the perimeter of a room when building a home? Discuss these purposes together.

See more lesson plans and resources: BrainPOP Educators.

Perimeter Teacher Activities

© 1999-2012 BrainPOP. All rights reserved.

Get into Shapes

Have pairs of students draw small shapes on paper or collect several small classroom objects to find their perimeter in inches, centimeters, or nonstandard units. One student can measure, while another records the lengths and writes out the number sentence. Then together they can add the lengths to find the perimeter. Afterward, have students swap roles to measure another drawing or object. If possible, have each pair draw bigger shapes on butcher paper or choose a few large classroom objects and repeat the activity using feet or even yards. This can also be a good opportunity for students to practice using calculators. Afterward, compare and contrast the perimeter of various objects that were measured. Did any two objects have the same perimeter even though they were different shapes? How is this possible?

Challenge your students to draw as many shapes as they can with a perimeter of 10 inches or centimeters. Encourage children to be creative, reminding them that shapes can have many, many sides! For example, a shape with 10 sides can have a perimeter of 10 centimeters if each side is 1 centimeter long. You may want students to double check each others' shapes to make sure the shapes have a perimeter of 10.

Perimeter Family Activities

© 1999-2012 BrainPOP. All rights reserved.

Measure for Measure

Measure and calculate the perimeter of different objects in your house, such as a placemat, rug, or picture frame. Then choose a room in your home and find it’s perimeter. You could even compare different areas—which room in your house has the greatest perimeter? You can use a tape measure or nonstandard units such as footsteps.

In the Field

What's the perimeter of a soccer field or a basketball court? Find out together by measuring the lines on the field or court. You may wish to use nonstandard units such as footsteps if you do not have a tape measure that is long enough. After measuring a few places, you may want to estimate the perimeter of another location in your community, and then measure to find the exact answer. What might the perimeter of your local playground be? Make a prediction and measure to see if you’re right!