I was tempted to call this lesson plan “Find the perimeter and leave me in peace” because I was asked if I had any lessons students could do on their own. By this point, many parents are getting tired of interrupting their own work every 5 minutes to help their children with math problems.
Finding the perimeter activities can be fun in school or out
No, really, I’m serious. You need three things for this activity.
- A piece of paper
- A pen or pencil
- A phone
A measuring device like a ruler, measuring tape or yardstick is optional but would be fun to have.
Step 1: Watch the perimeter video
Step 2. Make a table like in the example below
| OBJECT | Length | Width | |
| Seat of chair | |||
| Table |
For this exercise, every object should be a rectangle. Be prepared for the question,
“Is a square a rectangle?”
– every third-grader , ever
Yes. Yes it is. If you want to get technical about it, a rectangle is a quadrilateral with four 90 degree angles. Or you could just say yes, a rectangle is a shape with four sides that are not slanted and a square definitely has four sides and is not slanted.
Step 3. Go measure 10 rectangles in the house
This is where the physical education comes in. Tell your child he or she has 10 minutes to complete the table with 10 items. An item can be as small as a box of candy or as big as the floor of a room. For each rectangle, write down the name of the object, the length and the width. Just put the whole number. If it says 18 1/4 or 18 1/2 just put 18. You may be tempted to tell your child to just round it but remember, he or she may not have learned fractions yet. That’s a lesson for another day.
If you don’t happen to have a ruler, yardstick or tape measure, your phone probably has a Measure app. This comes by default with an iPhone and if you don’t see it right away look in the Utilities folder. To use it, point at a surface and click to select a point. Then, move the phone until you are at the end of what you want to measure.
Depending on how much exercise you want your child to get, the size of your house and how much peace you need (I won’t judge you), you may want to add a few rules like:
- None of the objects can come from the room you are currently in.
- They need to find rectangles in at least 3 different rooms
- They need to find at least one rectangle in the backyard/ garage/ basement.
Once you have shown your child how to use the measure app and they have the table and a pencil, set the alarm on your phone and tell them to go. The alarm will go off when the 10 minutes are up.
Check their number of rectangles and if they are a few short give an extra 2- 5 minutes to find the rest.
Step 4 Watch another video on perimeter
Why? Because I believe that kids often don’t remember something if they only heard it once.
Step 5: Compute the perimeter for each object you have measured
| OBJECT | Length | Width | Perimeter |
| Seat of chair | 20 | 17 | 74 |
| Table | 32 | 17 | 98 |
Your child does this, not you. You’ve already completed elementary school.
The perimeter video is in Making Camp Premium.
You can play it on the web or download it from the app store for free. You can download it from Google Play for $1.99 or email info@7generationgames.com and we’ll give you a discount code.
Reason with shapes and their attributes.
CCSS.MATH.CONTENT.3.G.A.1
Understand that shapes in different categories (e.g., rhombuses, rectangles, and others) may share attributes (e.g., having four sides) and that the shared attributes can define a larger category (e.g., quadrilaterals). Recognize rhombuses, rectangles, and squares as examples of quadrilaterals, and draw examples of quadrilaterals that do not belong to any of these subcategories.Apply the area and perimeter formulas for rectangles in real-world and mathematical problems. For example, find the width of a rectangular room given the area of the flooring and the length, by viewing the area formula as a multiplication equation with an unknown facto