document.write( "Question 1127875: For the following exercise, determine the function described and then use it to answer the question.
\n" ); document.write( "The surface area, A, of a cylinder in terms of its radius, r, and height, h, is given by A = 2πr^2 + 2πrh. If the height of the cylinder is 4 feet, express the radius as a function of V and find the radius if the surface area is 360ft.
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Algebra.Com's Answer #744416 by ankor@dixie-net.com(22740)\"\" \"About 
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determine the function described and then use it to answer the question.
\n" ); document.write( "The surface area, A, of a cylinder in terms of its radius, r, and height, h, is given by A = 2πr^2 + 2πrh.
\n" ); document.write( " If the height of the cylinder is 4 feet, express the radius as a function of V
\n" ); document.write( "the volume of a cylinder:\"V+=+pi%2Ar%5E2h\"
\n" ); document.write( "h = 4 ft
\n" ); document.write( "\"pi%2Ar%5E2%2A4+=+V\"
\n" ); document.write( "\"r%5E2+=+V%2F%284%2Api%29\"
\n" ); document.write( "\"r+=+sqrt%28%28V%2F%284%2Api%29%29%29\" or \"r+=+1%2F2\"\"sqrt%28%28V%2F%28pi%29%29%29%29\"
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\n" ); document.write( " and find the radius if the surface area is 360ft.
\n" ); document.write( "\"2%2Api%2Ar%5E2+%2B+2%2Api%2Ar%2A4+=+360\"
\n" ); document.write( "simplify, divide by 2
\n" ); document.write( "\"pi%2Ar%5E2+%2B+4%2Api%2Ar+=+180\"
\n" ); document.write( "divide both sides by pi
\n" ); document.write( "\"r%5E2+%2B+4r+=+180%2Fpi\"
\n" ); document.write( "\"r%5E2+%2B+4r+=+57.3\"
\n" ); document.write( "a quadratic equation
\n" ); document.write( "\"r%5E2+%2B+4r+-+57.3\" = 0
\n" ); document.write( "Use the quadratic formula, a=1; b=4; c=-57.3
\n" ); document.write( "Positive solution
\n" ); document.write( "r = 5.83 ft is the radius
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