Suzanna wants to measure a board, but she doesn't have a ruler to measure it. However, she does have several copies of a book she knows is 17 centimeters tall.

A: Suzanna lays the books end to end and finds that the board is the same length as 21 books. How many centimeters long is the board?

B: Suzanna needs a board that is at least 3.5 meters long. Is the board long enough? Explain.