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
Truncated to one significant figure, it's 9,000 .Rounded to one significant figure, it's 10,000.
0.00009893 to 1 significant figure = 0.0001