First:
c = [tex] \sqrt{a^{2}+b^{2} } [/tex]
We could square c to get rid of the square root.
[tex] c^{2} = a^{2} + b^{2} [/tex]
And then subtract [tex] a^{2} [/tex] from both sides
c ^ 2 - a ^ 2 = b ^ 2
Then square root both sides
[tex] \sqrt{ c^{2} - a^{2}} = b [/tex]
