0.000039 as you have to round it up. 3 and 8 are the significant figures but as you must round up, the answer becomes 0.000039.
It depends on how many significant digits you want to round it off to.
To round a number to 2 significant figures, you first need to look at the first two digits. In this case that is 3.5. The next step is to look at the third digit and assess if we need to round up. If the digit is 5, 6, 7, 8 or 9 you round up. Otherwise you leave the figures as they are (round down). In this case the third digit is 8, and so we do need to round up. Thus 3.582 rounded to 2 significant figures is 3.6
If your question was 'what is 216 to one significant figure', the answer would be 2. This is because the two means two hundred. If your number was 0.216 and you had to round it to one significant figure it would also be 2, but if your number is 0.203 and you had to round it to two significant figures you would say 20 this is because you only count the zeros as significant figures after an actual number. For example; 0.31 to two significant figures would be 31 but 0.301 to two significant figures would be 30.
There are 2 significant figures.
88930371.007 to 2 significant figures is 89000000
Rounded to 2 significant figures it is 0.043
8468 rounded to 2 significant figures is 8500
0.000039 as you have to round it up. 3 and 8 are the significant figures but as you must round up, the answer becomes 0.000039.
0.26
0.067
5200
To change 3.20 into 2 significant figures, simply round it to 3.2. The zero after the 2 is removed as it is not significant when there are only 2 significant figures.
7000.
54000
2700
rounded to 3 significant figures it would be .00750