Question 42758
Split the square in half diagonally to get a right angle.
{{{a^2 + b^2 = c^2}}}
{{{sqrt(20^2 + 20^2) = c}}}
{{{sqrt(400 + 400) = c}}}
{{{sqrt(800) = c}}}
{{{sqrt(2*2*2*2*2*5*5) = c}}}
{{{2*2*5*sqrt(2) = c}}}
{{{20*sqrt(2) = c}}}
About 28 feet ....