Question 1094711
.
<pre>
Let x be the length of the middle side (in mi units).


Then the length of the shortest  side is x-71 mi,
and  the length of the longest   side is (x+373) mi.


The "perimeter equation" is

x + (x-71) + (x+373) = 3065.


Simplify and solve for x:

3x + 302 = 3065 ====>  3x = 2763  ====>  x = {{{2763/3}}} = 921.


Middle   side is of         921 mi long,
shortest side is 921-71  =  850 mi long,
longest  side is 921+373 = 1294 mi long.


<U>Check</U>.  You need to check that all three "triangle inequalities" are valid.

        Please do it on your own.
</pre>