Pick the closest whole number to 8.6 that is not a fraction. In this case it is 9.
9000
10000000
100
It is 0 0.00005
The answer is 400 but these websites on related links are good.
It is 0.01
7000
0.9
0.1
2,000,000
9000
10000000
800
200
100
round to the first significant figure
I think your question is asking how you would round 17.521 to the nearest number with 1 significant figure...if that's the case, it would round to 10.