Let the other leg = y and the hypotenuse = z
Then by the Pythagorean theorem:
That expresses 49 as the product of two positive integers
with z-y less than z+y
49 can be written as the product of two positive integers
in only 3 ways:
,
,
but only the first way has the first factor smaller than the second.
So
Solve that and get z=25, y= 24
So the right triangle has legs 7, 24, and hypotenuse 25.
Edwin