Find the Missing Side of a Rectangle, when you know the Perimeter

For more like this go to https://www.letsdomath.ca/
It's an easy-to-use route to resources, faster than scrolling through videos on YT!

Perimeter of a Rectangle calculations are essential, but students can enjoy a challenge when they are given the perimeter and a single sidelength, and have to work out the remaining side.
In this video, we solve the remaining side by calculation, using the strategies from my video 'Finding the Perimeter of a Rectangle'. There is no 'guess and check' here.
1. Starting from the perimeter, we work backwards to find the missing side. We also check our work by adding up all the sides at the end. (Strategy 1)
2. (Strategy 2) Reversing the doubling strategy, we solve that missing side length. After the calculation, I go over the steps we took once more.
3. (Strategy 3) My favourite: finding the missing side by halving the perimeter first, then solving the missing side by subtraction. It's just the easiest way.
Please make sure to take notes to help yourself. 😃
If you plan to skip part of the video, please just scan through to your preferred strategy and soak it up fast.
CC: by me