The GCF is 1. There is no other number that those numbers have in common.
Hope this helps!!
The scale of the map is equal to 250 miles per 1.7 feet. or 250m/1.7ft. set up as a fraction.
Divide 250 by 1.7 to get how many miles are equal to just 1 foot.
250/1.7 = 147.058824 miles per 1 foot
Multiply that times 3.06 feet (the distance between C and D on the map)
147.058824m/1ft x 3.06ft = 450m
The actual distance between City C and City D should be 450 miles.