A lot of teachers don't teach SohCahToa anymore! this acronym will really help you. I'd suggest looking up how to use it, it'll make trigonometry WAY easier!
Answer:
The awswer is red. it only makes sense
He cut the lasagna into 15 pieces. If he cut 3 pizzas and he cut each one 5 times, then he would come out with 15 total slices (3x5)