The number 0.054698 expressed to one significant figure (sf) is 0.05, with 5 being the only digit considered significant.
To express the number 0.054698 to one significant figure (sf), we first identify the first non-zero digit, which is 5.
Therefore, the digit 5 is the only significant figure we will keep.
Other digits will be dropped, but since the next digit (4) is less than 5,
we do not need to round up. So, the number 0.054698 expressed to one significant figure is 0.05.