Measuring, Perimeter and Area

A grade 9 class I was in today was working on perimeter and area. They started by looking at these triangles and working out which one had the largest perimeter and largest area.

There was some good discussion about how to determine the area and perimeter, and some students used logic, while others measured on the screen using a variety of measuring tools (some conventional, and and some less so).

The next part of the lesson was to arrange desks according to the prompt on the screen, and measure the desks using unconventional items, and then to try it again and measure with more conventional tools.

Students got right into measuring! Some used bananas or cheese strings or markers, or hands, or feet to measure.

They wrote their work on the desks as they proceeded. There was a lot of great discussion about which sides contributed to the perimeter—only the outside edges!

Groups worked on presenting their calculations with units. This was the first time I’ve ever considered what a cheesestring squared would be.