I'm pretty sure you are asking for the value of b. Let's actually write it and then solve it:
[tex]10^2 + b^2 = 22^2[/tex]
Solving for b yields:
[tex]b = \sqrt{22^2-10^2} = \sqrt{484-100} = \sqrt{384} = 19.59[/tex]
So, b = 19.59. If you want the answer in simplified radical form, we can also do that:
[tex] \sqrt{384} = \sqrt{16*24} = 4 \sqrt{24} = 4 \sqrt{4*6} = 8 \sqrt{6} [/tex]
So, b = 8√6 = 19.59
