34.872 rounded and chopped to 1 sig fig is 30. The previous answer 34.8 is wrong, 34.8 is 34.872 chopped to 3 sig figs.
Any digit in a number that is not zero is classed as a significant figure e.g. your number above has 5 sig figs but if it was 30.072 it would only have 3 sig figs: 3, 7 and 2. When someone asks something to be taken to n sig figs they mean the first n significant figures of the number i.e. 103.42 to 2 sig figs would be 103, not 100.
Also, incase you don't know what I mean when i used the terms rounded and chopped above, rounding is when you round the number either up or down to the nearest sig fig so your number rounded to 2 sig figs would be 35. Chopping however is when you take however sig figs you need and chop the rest of regardless of how close the n+1th digit is to a higher sig fig. e.g. 34.372 is 34 chopped to 2 s.f. but 34.872 is also 34 chopped to 2 s.f. in fact if a number is virtually the same as a higher number it will get chopped to a lower one e.g. 34.999999999999999 chopped to 2 s.f. is 34, not 35!
654 rounded to one significant figure becomes 700.
1534 to 1 significant figure is 2000.
10920 to 1 significant figure is 10000
2300 rounded to 1 significant figure is 2000.
849 to 1 significant figure is 800. This is because the first non-zero digit is 8, so the significant figure is the hundreds place.
37.753 rounded to one significant figure becomes 40
It has 1 significant figure.
4252 to 1 significant figure is 4000.
4916 to 1 significant figure is 5000
Rounded to 1 significant figure it is 0.4
9753261 to 1 significant figure is 10,000,000
1150 to 1 significant figure is 1000
654 rounded to one significant figure becomes 700.
1534 to 1 significant figure is 2000.
1512 to 1 significant figure is 2000
When expressing a number to one significant figure, you round the number to the nearest power of 10. In this case, 9862 to one significant figure would be 10,000. This is because the first digit from the left is 9, which is closer to 10 than 10000.
0.00009893 to 1 significant figure = 0.0001