Question 12439
The Pythagorean theorem states that, for any right-triangle:

{{{c^2 = a^2 + b^2}}} where: c is the length of the hypotenuse and a & b are the lengths of the two legs.

If {{{c^2 = 6^2}}} and side a = side b, then:

{{{6^2 = a^2 + a^2}}} Add the a^2 terms.
{{{36 = 2a^2}}} Divide both sides by 2.
{{{18 = a^2}}} Take the square root of both sides.
{{{sqrt(18) = a}}}

So each side of the right-triangle is {{{sqrt(18) = 3sqrt(2)}}} and the hypotenuse is 6.