What is 69/25 as a terminating decimal

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?

How do you determine if an ordered pair is a solution to a given equation?

If sr is 4.5cm and tr is 3cm, what is the measure in degrees of angle s? a. 56.3 b. 33.7 c. 41.8 d. 48.2