How to Teach Geometric Perimeter to Kids

Perimeter is the distance around something, like a fence. Teach children to understand that we measure perimeter by looking at the sides of objects and adding them together. The perimeter is like the outline of a shape. Follow these tips to teach geometric perimeter to kids.

Instructions

Difficulty: Moderate

Things You’ll Need:

• Pencil
• Paper
• Ruler

1. Look at the sides of an object. They all form together to make a shape. If we want to know the distance around an object, we measure the sides and add the lengths. No matter how odd the shape is, you just add the sides together.
2. Point out common objects that have sides like a cereal box, a play room, a table, and a backyard. Show children that we have many shapes around us. Ask the child to guess the measurement of each side. Talk about estimation. Then think of ways to measure each object.
3. Talk about the reasons we would measure things. For example, we might measure our yard so that we can install a fence around it. We need to know the length of the sides so that we order the right amount of wood.
4. Explain that there are different units of measurement. In the USA, they use inches, feet and yards to measure perimeter. Other countries use the metric system which includes centimeters and meters.
5. Measure things around your house with a ruler. Make sure you find all sides. Add the sides together to find the perimeter. Show how some things have parallel lines which means they may have equal lengths like in a rectangle or square.
6. Teach the perimeter formula for a square or rectangle. That is, Perimeter = a + b + c + d. Each letter stands for one side of the object. A triangle only has three sides so the formula is Perimeter = a + b + c.
7. Explain that squares have four equal sides. You can find the length of one side and multiply it by four. Explain that rectangles have two short sides and two long sides so you can find the length of a short side and multiply it by two. Then you can find the length of a long side and multiply it by two. Add the two rectangle sums together to find the perimeter.
   
   Write the formula like this: Perimeter = 2l + 2w
   = 2(5) + 2 (2)
   = 10 + 4
   = 14
   
   
   
8. Make up questions for kids to solve. For example, if one side of the square is 2 feet, what is the perimeter of the square? Explain how you answer this by using the formula. All sides of a square are equal so the perimeter is 2 + 2 + 2 + 2 = 8.

Tips & Warnings

• To find the perimeter of any shape with lines, add all the sides together.