## Sunday, October 26, 2008

### Project Idea: Using Formulas to Find Area, Perimeter and Circumference

In Algebra I, teachers often have to teach quite a bit of basic geometry. Sometimes, this is part of a far too ambitious state curriculum that covers too many topics in too little depth. This is also to prepare students for taking Geometry next year, standardized tests, and college entrance exams. Of course, solving expressions for given values is an essential part of basic algebra as well. So although finding area and perimeter of polygons as well as area and circumference of circles is a bit tangential to algebra, it's a good tangent to be on.

As we finish up our first quarter of the year, I thought a unit covering these topics would fit in well with the rest of the foundation we're building. I wanted to have a simple assessment to wrap things up while helping students to retain the information in the long term, so I drew on an idea from my former department head.

She had students create a formula book. The book contained every formula from the sheet given to students for the TAKS (the Texas state standardized test). Students would then show an example of a problem where they would use they formula. Well, if it ain't broke, don't fix it, right?

My version of the formula book contains formulas and examples for perimeter of any shape; area of squares, rectangles, parallelograms, triangles, trapezoids, circles and compound shapes; and circumference of circles. Each page had a title, formula and examples (2 different ones for most). As for what the book would look like, that was a creative decision for each students. Most opted to fold a regular size paper in half and staple the middle like a book binding.

I provided colored paper, markers, crayons, rulers and the like. My kids were given 2 block classes (about 2 hours total) to complete it, although I think that was more than enough time. I did create an example book and put various examples on the board to help students who had trouble getting started, but it was overall a very self-directed project. Judging by the completed books I received, I think this worked exactly as intended. Click below for the handout: