Question 880131
x and y are the dimensions.
{{{xy=2400}}} and {{{2x+2y=200}}}.  


The perimeter equation simplifies to {{{x+y=100}}}.
{{{y=100-x}}};
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{{{xy=2400}}}
{{{x(100-x)=2400}}}
{{{100x-x^2=2400}}}
.
.
You do the rest.