This is a fun game to play with your students to encourage deductive reasoning and critical thinking skills. It covers classifying triangles, angles of triangles, congruent triangles, and isosceles and equilateral triangles. Also included is a bit of review (midpoint theorem, segment addition postulate, angle relationships, etc).
To play, print out this sheet (I printed mine on pretty colored card-stock because I do not have a laminator). I suggest printing one sheet per group of 2-4. Cut out the 9 squares and place them in a plastic baggie. Once you have made enough sets for your groups you are ready to play! Simply give each group a baggie and tell them that they must create a 3x3 square and all of the phrases/definitions on the sides of each square must match up to the sides of the squares that they are next to. (Maybe give one example)
The sheet you download is the answer key (which is why you must mix up the 9 cut-out squares). I teach standard and honors Geometry classes, so to differentiate the game I will tell my standard classes a hint--the numbers on the cards stay right-side up (no upside down or sideways numbers to reach the answer). I will not tell this to my honors classes.