How do you use cos tan and sin. I know what they are and if you gave me a right triangle, I'd be able to find its cos sin and tan but how do you use it in "real life" I guess. Like for example in a formula and such.
Trigonometry would be used in many different ways. It is used for surveying and for all types of engineering.
If a bridge is not to fall down than all the stresses etc on it need to be calculated accurately. Trigonometry is an essential tool here. It is used in many other fields as well.