Answer:
1020
Step-by-step explanation:
well, the first three significant figures stops at the 102, so round the 1023.4567 to a whole number which just becomes 1023
then, round the answer so you only have the 102, so you would round down since 4 or less, which 3 is less than 4, you round down, and you would get 1020
that last 0 is not a significant figure because it does not have a decimal point or any other number following after it--any 0s at the end of a number are not significant if there is no decimal point or other number after them.