Answer
a) 65.7
b) 65.7
c) 65.8
d) 65.8
Work Step by Step
a) you are given 65.74, in order to bring it down to 3 sig digits you must round down the four which would give you 65.7.
b) you are given 65.749, in this case, you ignore the 9 at the end and just pay attention to the four which would keep it down at 65.7.
c) you are given 65.75, it is evident that you have to round up because the five is right after.
d) it is the same scenario as c but it has a zero at the end which doesn't affect it at all.