Find the sum of the first 41 terms of the following series, to the nearest integer.
4, 12, 20,...

Find the sum of the measure of the interior angles of a polygon of 9 sides ; of 32 sides

Problem fathi wants to print out a pdf document that is 48 pages long. to save paper, he decides to print on both sides of each sheet and to print two pages on each side of the sheet. how many sheets of paper will he need?

Does the point (1, sqrt 7) lie on circle shown.