we know that
Applying the law of cosines
c²=a²+b²-2*a*b*cos C
in this problem
c--------> is the the distance between the docks in meters
a---------> 650 meters
b--------> 750 meters
C---------> 60°
substitute in the formula above
c²=650²+750²-2*650*750*cos 60------> c²=497,500---------> c=705.34 m
c=705 meters
therefore
the answer is
the distance between the docks in meters is equal to 705 m