On Wednesday, I started the class with this:

I want to build a deck that will come out over my back yard. I want a cool design, but also one that takes up the least amount of area. The trouble is I don’t know how to find the area of these irregular shapes.

Students were seated in groups to figure out this problem. I handed each student this prompt, along with 2 deck designs, both of which were irregular shapes.

I didn’t give much information other than that. As I walked around the room, I heard lots of great ideas. Many figured out that they could break the shapes into smaller shapes, such as a rectangle, triangle, trapezoid. Other groups thought to “enclose” the whole shape, as in make it a full rectangle, and then subtract the portion not needed. I was glad to see the different methods of going about finding the area. After about 10 minutes of investigation, several groups shared their ideas with the class.

## About Gretchen Simmerson

Middle School math teacher living in Austin, Texas.