Probabliilty of picking a marble

Aparallelogram has two side lengths of 5 units. three of its sides have equations y = 0, y = 2, y = 2x. find the equation of the fourth side.

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.

Can someone answer it, and plot it, for 20 points and brainliest answer? p. s. they're the same ! : )