Learn the definition of polygon, and start to flesh out a heirarchy of quadrilaterals. Relate to heirarchies in nature. Classification is fundamental to the way humans think, so being comfortable with this concept is very important, not only to the studentâ€™s further exploration of math, but to reasoning in general. Here's a video covering all the concepts necessary to introduce polygons.

The Common Core is too vague. Which properties?

Watch these Khan Academy videos:

Quadrilateral types by Khan Academy

Next, give your students this challenge:

Tangram Tangle by NRICH: Additionally, ask your students to classify each shape they're able to make.

Conclude by leading this investigation:

Taxi Cab Squares

by MathPickle

5.G.B.4: Classify two-dimensional figures in a hierarchy based on properties.