How many significant figures are there in the measurement 238.230 kg?
Six significant figures.
The first things to look for here are non-zero digits, which as you know are always significant.
This measurement has a total of
so right from the start you know that it will have at least five significant figures.
Now focus on the trailing zero. Trailing zeros are zeros that follow a non-zero digit and are not followed by other non-zero digits.
When trailing zeros follow a non-zero digit and a decimal place, they are considered significant. This means that your measurement will contain
#238.230 ->#five non-zero digits and one significant trailing zero