Since this is an isosceles right triangle the sides have equal length. From the Pythagorean Theorem:
h^2=x^2+y^2, where h=hypotenuse, x and y are the side lengths.
Since x=y=s and we are told that h=22 we can say:
2s^2=22^2
2s^2=484
s^2=242
s=√242
s=√(121*2)
s=√(11*11*2)
s=11√2
