document.write( "Question 737399: A lifeguard is interested in enclosing a rectangular swimming area along the beach. The swimming area will be enclosed using 72m of floating rope and will be bordered on one side by the beach: that is the problem \r
\n" ); document.write( "\n" ); document.write( "these are the questions
\n" ); document.write( "a. Draw a sketch to model the situation
\n" ); document.write( "b. Find the dimensions (length and width) that provide the maximum area for swimming.
\n" ); document.write( "c. What is the maximum area available for swimming?\r
\n" ); document.write( "\n" ); document.write( "Please could someone help me with this today
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Algebra.Com's Answer #450475 by ankor@dixie-net.com(22740)\"\" \"About 
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A lifeguard is interested in enclosing a rectangular swimming area along the beach.
\n" ); document.write( " The swimming area will be enclosed using 72m of floating rope and will be bordered on one side by the beach: that is the problem these are the questions
\n" ); document.write( ":
\n" ); document.write( "a. Draw a sketch to model the situation
\n" ); document.write( "I'll let you handle this
\n" ); document.write( ":
\n" ); document.write( "b. Find the dimensions (length and width) that provide the maximum area for swimming.
\n" ); document.write( "Only 3 sides are required therefore
\n" ); document.write( "L + 2W = 72
\n" ); document.write( "L = (72-2W)
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\n" ); document.write( "c. What is the maximum area available for swimming?
\n" ); document.write( "A = L * W
\n" ); document.write( "Replace L with (72-2W)
\n" ); document.write( "A = W(72-2W)
\n" ); document.write( "A quadratic equation
\n" ); document.write( "A = -2W^2 + 72W
\n" ); document.write( "Max area occurs on the axis of symmetry, find it using formula: x = -b/(2a)
\n" ); document.write( "W = \"%28-72%29%2F%282%2A-2%29\"
\n" ); document.write( "W = 18 m is the width that gives max area
\n" ); document.write( "then
\n" ); document.write( "L = 72 - 2(18) = 36 m is the length for max area
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\n" ); document.write( "Actual max area: 18 * 36 = 648 sq/m
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\n" ); document.write( "If you graph the equation you can see that max area occurs when x=18 (width)
\n" ); document.write( "\"+graph%28+300%2C+200%2C+-10%2C+50%2C+-100%2C+700%2C+-2x%5E2%2B72x%29+\"
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