In a class of 18 students the teacher wants to form a group of 4 to answer homework questions. how many different possible groups are there?

In the diagram, the measure of angle 9 is 85° which angle must also measure 85°?

The head librarian at the library of congress has asked her assistant for an interval estimate of the mean number of books checked out each day. the assistant provides the following interval estimate: from 740 to 920 books per day. what is an efficient, unbiased point estimate of the number of books checked out each day at the library of congress?

9/10 divide by -3/15 as a mixed number