Answer:
Seven
Explanation:
The rules for significant digits are:
- Non-zero digits are always significant.
- Zeros between significant digits are also significant.
- Trailing zeros are significant only after a decimal point.
Here, the 2, 4, 9, and 2 are significant because they are non-zero digits.
The first two 0s are significant because they are between significant digits.
The last 0 is significant because it is a trailing zero after a decimal point.
Therefore, all seven digits are significant.
