Question

how many significant figures are in the measurement 16.400 g? 16.400 has ? significant figures.

Explanation:

Step1: Identify non-zero digits

Non-zero digits (1,6,4) are significant: 3 figures.

Step2: Identify trailing decimals

Trailing zeros after decimal (0,0) are significant: 2 figures.

Step3: Sum significant figures

Add counts from steps 1 and 2.
$3 + 2 = 5$

Answer:

5