The fact that there is a trailing zero and the number is not given as 6.02310 is indicative that the number is accurate to the nearest hundred thousandths, not just the nearest ten thousandths. Therefore, it has six significant figures.
4
It has 3 significant digits.
3 significant digits.
It has two significant digits.
Five. All nonzero digits are significant and zeros in between significant digits are significant.
Five. All nonzero digits are significant and zeros in between significant digits are always significant.
Five. All nonzero digits are significant and zeros in between significant digits are always significant.
Five. All nonzero digits are significant and zeros in between significant digits are always significant.
Three significant digits.
50.4 has 3 significant digits.
There are 3 significant digits in 20.0
3.12724 has 6 significant digits.