3 of them.
778
3 significant figures.
9
9.999 to 3 significant figures is 10.00
4,566 to 3 significant figures is 4,570.
3 of them.
Yes, that is correct.
33.0
The correct answer is 1960
778
How many significant figures are in 20.8
If the zeros are significant figures then 900 is correct to 3 significant figures. If rounding off has occurred then the answer could be 1 sf or 2sf. For example : If the original number was 903 and rounding off to the nearest ten was required then 900 is correct to 2 significant figures. If the number was 927 and rounding off to the nearest hundred was required then 900 is correct to 1 significant figure.
The correct answer is 2. The three zeros between the decimal point and the 1 are place holders but they are NOT significant digits. See, for example, the Wikipedia link.
6040 has 3 significant figures.
32.2
There are 4 of them