To determine the number of significant digits in the number 405, let's carefully follow the rules for identifying significant figures:
1. Non-zero digits are always significant.
2. Any zeros between significant figures are also significant.
3. Trailing zeros in a number containing a decimal point are significant.
For the number 405:
- The digits '4' and '5' are non-zero, so they are significant.
- The digit '0' is between the significant figures '4' and '5', making it significant as well.
Therefore, we count all the digits in the number 405:
- 4 (significant)
- 0 (significant)
- 5 (significant)
This gives us a total of 3 significant figures.
So, the number of significant digits in 405 is:
c) 3
