I am new to trigonometry,so sorry if i don't quite get it.

I know that like cos (60)=.5, and i use the tables for my current problems, but i was wondering..

Is there a way to find it out by yourself, and not look at the tables? Like is there a formula for this?

For example,

I need to find x.

So i do cos (60) =x/13

cos(60) x 13=x

How do i find cos(60)? i know it is .5, but i can't memorize the table. Thanks in advance

EDIT: nvm haha that made no sense i get it now