Hi,
There are 10 significant digits in the measurement of 9478.983560 cm. A significant number is a number that is not a zero, however, in this problem you see there is one zero and that counts as a significant number because it is after a whole number.
In conclusion, a significant number is a number that is not a zero, however the only exception to this rule is that it must be after a whole number for it it to count as significant.
