document.write( "Question 1113494: A canvas camping tent is to be constructed in the shape of a pyramid with a square base. A pole of height h = 12 feet will form the center support, as illustrated in the figure. Find the length x of a side of the base so that the total amount of canvas needed for the sides and bottom is 864 ft^2. \n" ); document.write( "
Algebra.Com's Answer #728572 by greenestamps(13206)\"\" \"About 
You can put this solution on YOUR website!


\n" ); document.write( "The base is a square of side length x; its area is x^2.

\n" ); document.write( "The sides of the tent are four congruent triangles with base x.
\n" ); document.write( "The altitude of each triangle is the slant height of the pyramid.
\n" ); document.write( "With the square base of side length x and a center pole of 12, the slant height is the hypotenuse of a right triangle with legs x/2 and 12.

\n" ); document.write( "So the area of each triangular side of the tent is one-half base times height:
\n" ); document.write( "\"%281%2F2%29%28x%29%28sqrt%28%28x%2F2%29%5E2%2B12%5E2%29%29\"

\n" ); document.write( "The total surface area of the four sides and bottom of the tent is then
\n" ); document.write( "\"x%5E2%2B2x%28sqrt%28%28x%2F2%29%5E2%2B12%5E2%29%29\"

\n" ); document.write( "This total surface area is to be 864:

\n" ); document.write( "\"x%5E2%2B2x%28sqrt%28%28x%2F2%29%5E2%2B12%5E2%29%29+=+864\"
\n" ); document.write( "\"2x%28sqrt%28%28x%2F2%29%5E2%2B12%5E2%29%29+=+864-x%5E2\"
\n" ); document.write( "\"4x%5E2%28x%5E2%2F4%2B144%29+=+746496-1728x%5E2%2Bx%5E4\"

\n" ); document.write( "(Looks ugly -- but the x^4 terms will cancel, leaving a simple quadratic equation...)

\n" ); document.write( "\"x%5E4%2B576x%5E2+=+746496-1728x%5E2%2Bx%5E4\"
\n" ); document.write( "\"2304x%5E2+=+746496\"
\n" ); document.write( "\"x%5E2+=+324\"
\n" ); document.write( "\"x+=+18\"

\n" ); document.write( "Answer: The side length of the tent is 18 feet.

\n" ); document.write( "(by the way... I don't think this is a CAMPING tent!!)
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