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put this solution on YOUR website!From the Pythagorean theorem,

.
From the perimeter condition, x + y + 600 = 1400, or y = 800 - x.
Substitute this into the 1st equation, to get

,
<==>

,
<==>

.
Using the quadratic formula, we get

.
If

, then

.
If

, then

.
Hence there is only 1 pair of values for the legs, and those are

and

.