This week in geometry one of my students is learning about the different "centers" in a triangle (orthocenter, circumcenter, incenter, etc), as well as the midsegments theorem and triangle inequalities.

To help him visualize why all of these things are true, I had him cut out an acute triangle, an obtuse triangle, and a right triangle and use these to illustrate the concepts.

For triangle inequalities, we worked with different lengths of string to see why some combination of leg lengths and some do not.

These are both quick, easy ways that help students understand beyond the words and definitions what we are talking about!