Are ratios 15:20 and 1:10 equivalent

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

Statement: if two points are given, then exactly one line can be drawn through those two points. which geometry term does the statement represent? defined term postulate theorem undefined term

Find the value of x. round the length to the nearest tenth