Answer:
18.8651
Explanation:
(im not the best at explaining, so sorry if i dont explain it well, but ill try!)
so rounding a number to a certain amount of sig figs is a pretty easy concept to grasp, in my opinion.
ex: lets say you need to round 231.45 to 3 sif figs.
basically what you have to do in this situation is count the digits up to you get to the 3rd digit.
check if the digit that follows it is smaller or bigger than 5 to see if the 3rd number will stay the same or has to go up a number.
for this problem the third digit is 1, and the digit that follows it is 4. but 1 is less than 4, so that means that it will stay as 1.
thus the answer would be 231.
if that didnt make sense, comment on my answer and ill try to give you more examples