Question 131851
Use the Pythagorean theorem
Given a right triangle with sides a and b  and hypotenuse c

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

In the triangle, both sides and b have a length of A
so
{{{A^2 + A^2 = c^2}}}
{{{2A^2 = c^2 }}}
{{{sqrt(2)* A = c }}}