A rectangle has two pairs of equal sides. It has four right angles (90°). The opposite sides are parallel. The diagonals bisect each other. A parallelogram has two pairs of equal sides. It has two ...

A rectangle has two pairs of equal sides. It has four right angles (90°). The opposite sides are parallel. The diagonals bisect each other. A parallelogram has two pairs of equal sides. It has two ...

Construct a convex octagon with four right angles. It probably says a lot about me as a teacher that I assign problems like this. I watch as students try to arrange the right angles consecutively.

This week, I want you to step back in time — to the years in grade school or high school geometry classes. That’s probably when you learned about polygons — and perhaps the last time you thought about ...