Question 99585
{{{c=sqrt(a^2+b^2)}}} Start with the given equation



{{{c^2=(sqrt(a^2+b^2))^2}}} Square both sides. Notice the square and the square root cancel out on the right


{{{c^2=a^2+b^2}}} Simplify



{{{c^2-b^2=a^2}}} Subtract {{{b^2}}} from both sides



{{{sqrt(c^2-b^2)=sqrt(a^2)}}} Take the square root both sides. Notice again the square and the square root cancel out on the right




{{{sqrt(c^2-b^2)=a}}} Simplify



So our answer is {{{a=sqrt(c^2-b^2)}}}