The formula
[tex]c = \sqrt{ a^2 + b^2 }[/tex]
represents the length of the hypotenuse of a right triangle with side lengths a and b, and we have to solve for b .
First we need to get rid of the radical and for that, we do squaring on both sides. That is
[tex]c^2 = a^2 + b^2[/tex]
Now we need to get rid of a^2 and for that we do subtraction.
[tex]b^2 = c^2 - a^2[/tex]
And finally we need to get rid of square, and for that we take radical to both sides
[tex]b = \sqrt{ c^2 -a^2 }[/tex]
