I don’t have a pen and paper so I can’t do this. But I can tell you what to do. Use Pythagoras’ Theorem to work it out.
a2 + b2 = c2
The c2 is the hypotenuse squared and the a2 is the other measurement so
(2 x 2) + (b x b) = 100
4 + (b2)= 100
b2 = 96
b = 9.78
Answer = 9.78