Final answer:
The measurement 811.40 grams contains five significant figures, as determined by the standard rules for significant figures which include counting all nonzero digits, zeroes between significant digits, and trailing zeroes after a decimal digit.
Step-by-step explanation:
The question asks how many significant figures are in the measurement 811.40 grams. To determine this, we use the rules of significant figures:
- All nonzero digits are considered significant (Rule 1).
- Any zeroes between significant figures are significant (Rule 2).
- Trailing zeroes in a decimal number are significant (Rule 3).
Applying these rules:
- The number 811.40 has three nonzero digits (8, 1, and 1), which are all significant.
- The zeros after the decimal point and between significant digits (4 and 1) are also significant.
- There is one trailing zero after a decimal digit (4), which is significant.
Therefore, the measurement 811.40 grams has five significant figures.