Question 715260
Hi Doug
to find the diagonal of a square
we use pythagoras' theorem.
Draw a square and draw in the diagonal! look for the triangle!
Pythagoras theorem is {{{a^2+b^2=c^2}}} where and and b are the lengths of the short sides and c is the length of the hypotenuse.
so, substituting values  we get
{{{15^2+15^2=c^2}}}
therefore
{{{225+225=c^2}}}
so
{{{c^2=450}}}
to find c we take square roots i.e.
{{{c=sqrt(450)}}}
using a calculator we find
c=21.21 m to 2 decimal places