Math question

Hey I have question and I bet you can solve it.
Some people are going to fire off a rocket and they want to know the height of it. They want to create a program using a math formula that will help them do this.
They will have 3 angles equaling 180 and they will also have the distance from a point and the rocket.
I don't know what formula they could use to do this and I was hoping you could help.

So if a/b=tan(t) and t=60 and b=450
a/450=.32 (rounding)
a=450x.32
a=144ft