Why you can compare only the numerators

Which function is shown in the graph below?

Describe in detail how you would construct a 95% confidence interval for a set of 30 data points whose mean is 20 and population standard deviation is 3. be sure to show that you know the formula and how to plug into it. also, clearly state the margin of error.

If sr is 4.5cm and tr is 3cm, what is the measure in degrees of angle s?