Question 1114191
I should end up with a square to maximize area.
The perimeter is {{{ P = 700 }}} ft
{{{ P = 2W + 2L }}}
{{{ 2W + 2L = 700 }}}
{{{ 2L = 700 - 2W }}}
{{{ L = 350 - W }}} ft
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The area, {{{ A = W*L }}} 
{{{ A = W*( 350 - W ) }}}
{{{ A = -W^2 + 350W }}} ft2
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The formula for the W-value of the vetex,
( maximum in his case ) is
{{{ W[max] = -b/(2a) }}} when the general form is:
{{{ y = a*x^2 + b*x + c }}}
{{{ W[max] = -350/(-2) }}}
{{{ W[max] = 175 }}}
and
{{{ L[max] = 350 - 175 }}}
{{{ L[max] = 175 }}}
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{{{ A[max] = W[max]*L[max] }}}
{{{ A[max] = 175*175 }}}
So the max area is a square. You can calculate
and check my math.
Note also:
{{{ P = 2W + 2L }}}
{{{ P = 2*175 + 2*175 }}}
{{{ P = 700 }}}
as it should