document.write( "Question 62777: Could someone please help me with this. I just don't get algebra, but i'm getting better.
\n" ); document.write( "John has 300 feet of lumber to frame a rectangular patio (the perimeter of a rectangle is 2 times length plus 2 times width). He wants to maximize the area of his patio (area of a rectangle is length times width). What should the dimensions of the patio be, and show how the maximum area of the patio is calculated from the algebraic equation. \r
\n" ); document.write( "\n" ); document.write( " Show clearly the algebraic steps which prove your dimensions are the maximum area which can be obtained. Use the vertex formula to find the maximum area.
\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #43623 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
2*length+2*width=300
\n" ); document.write( "Divide thru by 2 to get:
\n" ); document.write( "length+width = 150
\n" ); document.write( "Solve for width:
\n" ); document.write( "width=150-length
\n" ); document.write( "--------
\n" ); document.write( "Let the length be \"x\".
\n" ); document.write( "Then the width = \"150-x\"
\n" ); document.write( "---------
\n" ); document.write( "Area=(length)(width)
\n" ); document.write( "Area=x(150-x)
\n" ); document.write( "Area=-x^2+150x
\n" ); document.write( "--------
\n" ); document.write( "This is a quadratic with a=-1 and b=150
\n" ); document.write( "Maximum area occurs when x=-b/2a
\n" ); document.write( "x=-150/(-2)=75
\n" ); document.write( "--------
\n" ); document.write( "Dimensions are
\n" ); document.write( "width = 75 ft.
\n" ); document.write( "length = 150-75=75 ft.
\n" ); document.write( "The maximum area is 75^2=5625 sq ft.
\n" ); document.write( "----------------
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( "
\n" );