One of the hardest things in trigonometry is memorizing which ratio goes with which function. This activity allows you to track student progress quickly and easily. Hand each student a card as they come in the classroom. When the bell rings, have them find their match. It also gets the students moving and, hopefully, talking about the difference between the functions.Hint: make sure that you hand out an even number so you don't have several students with no match. I usually prepare them ah