This is a great review for the 7th grade Measure Figures Unit. It included 6 geometry centers that allow kids to investigate triangles, the facts they must know about triangles to find missing sides, and special angles such as supplementary and complementary, similar figures, and solving for x. I also added a 7th center for scale/proportional reasoning. I gave the kids two full days, they were required to do 3 centers per day, and had homework if they didn't.
The directions I included are ideal and different than how I've done it. It's flexible anyway!