Question 1126259
Basic approach design: use parameter=sum of all side lengths.
Since both the shortest and longest sides' lengths are associated with the medium one, we assign variable x to the midium one, in order to intepret everything easier.
And BOOM!
(x-74)+x+(x+372)=3070
x=924 mi.

short:850
medium:924
long:1296.

That's how I think about solving this sort of problem. Hope it helps!