#### Answer

3

#### Work Step by Step

Apply the rules on page 162 of the book to find the significant digits (the accuracy) of the measurement 5.60 cm.
We use rule #1: all non-zero digits are significant. Thus, "5,6" are significant.
We also use rule #4: all zeros to the right of a significant digit and decimal point are significant; that is, we have here 1 zero which is significant.
Thus, there are 3 significant digits.