step 1
Find out the hypotenuse
Applying the Pythagorean Theorem
Let
H -----> hypotenuse

Part b
find an irrational length of one of the sides that result in the rational hypotenuse
For s=√2 -----> is an irrational number
but
H=√2*√2=2 -----> is a rational number
Part a
Find the rational length of one of the sides that result in a rational hypotenuse
Remember that
The product of a rational number and an irrational number is always irrational.
therefore
there is no rational number for one of the sides that result in a rational hypotenuse