Three: 3, 9 and 0.
10 significant figures.
0.0310 has 3 significant figures.
4
3
10800 meters has 3 significant figures.
2 of them.
4 significant figures.
10 significant figures.
There are 5 significant figures.
5 significant figures.
Three significant figures.
Four significant figures.
Four significant figures.
There are 5 significant figures.
It has 4 significant figures
4 significant figures.
3 significant figures.