The diameter of a gong is 20 inches. Find the approximate circumference of the gong, using 3.14 for p. Then find the exact circumference of the gong.

Somone me i want to know what 18 hours out of 24 hours in a fraction

He that is measured at 220° is a reflex angle. the opposite angle is obtuse. find the measure of obtuse .

Quick! a survey of 57 customers was taken at a bookstore regarding the types of books purchased. the survey found that 33 customers purchased mysteries, 25 purchased science fiction, 18 purchased romance novels, 12 purchased mysteries and science fiction, 9 purchased mysteries and romance novels, 6 purchased science fiction and romance novels, and 2 purchased all three types of books. a) how many of the customers surveyed purchased only mysteries? b) how many purchased mysteries and science fiction, but not romance novels? c) how many purchased mysteries or science fiction? d) how many purchased mysteries or science fiction, but not romance novels? e) how many purchased exactly two types of books?