No need to apologize, you’re here to learn!
I will break this down to make it easier to follow.
Theres a few important acronym here that will help, SOHCAHTOA.
Sin Opposite over Hypotenuse
Cosine Adjacent over Hypotenuse
Tan Opposite over Adjacent
This trick helps to remember how the trig functions are defined from a right triangle. If you want the tangent of angle B then you know its the length of the opposite side over the adjacent side!
So imagine a triangle with 3 sides: a, b, c and c is the hypotenuse
Sin(X) = a/c
Cos(X) = b/c
Tan(x) = a/b
Now it happens that if i divide sin(x) by cos(x) that is (a/c)/(b/c) = (a/c)*(c/b) = a/b = tan(x). So we can use this to evaluate the expressions!