Show that radius of gyration for a uniform circular disc

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.

In a column proof the right column states your reasons

What is the solution to the equation e3x=12? round your answer to the nearest hundredth