# Question #f3fc1

Sep 8, 2017

2

#### Explanation:

Significant digits are numbers that have been actually measured.

In $0.000 000 000 51$ only the 5 and 1 have actually been measured. the ten zeros are place holders. The zeros have not been measured they only give the value of the digits that have been measured.

If there were zeros to the right of the 51 those zeros would be significant. The zeros to the right would not change the value of the 51 digits so the only reason for writing zeros to the right of measured values is that the zeros have actually been measured.