document.write( "Question 900733: The radius of the base of each of two right circular cones is 8 inches. The altitude of the first cone is 9 greater than that of the second cone and its slant height is 7 inches greater than that of the second. Find the altitude of the taller cone. \n" ); document.write( "
Algebra.Com's Answer #546554 by ankor@dixie-net.com(22740)\"\" \"About 
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The radius of the base of each of two right circular cones is 8 inches.
\n" ); document.write( " The altitude of the first cone is 9 greater than that of the second cone
\n" ); document.write( " and its slant height is 7 inches greater than that of the second.
\n" ); document.write( " Find the altitude of the taller cone.
\n" ); document.write( ":
\n" ); document.write( "This can be done by considering two right triangles, using pythag formulas
\n" ); document.write( "let x = the height of taller cone
\n" ); document.write( "then
\n" ); document.write( "(x-9) = the height of the smaller cone
\n" ); document.write( "The slant dimensions are the hypotenuses
\n" ); document.write( "\"sqrt%28x%5E2%2B8%5E2%29\" - 7 = \"sqrt%28%28x-9%29%5E2+%2B+8%5E2%29\"
\n" ); document.write( "\"sqrt%28x%5E2%2B64%29\" - 7 = \"sqrt%28%28x%5E2-18x%2B81%29%2B64%29\"
\n" ); document.write( "\"sqrt%28x%5E2%2B64%29\" - 7 = \"sqrt%28%28x%5E2-18x%2B145%29%29\"
\n" ); document.write( "square both sides
\n" ); document.write( "\"x%5E2+%2B+64+-+14sqrt%28x%5E2%2B64%29+%2B+49+=+x%5E2+-+18x+%2B+145\"
\n" ); document.write( "subtract x^2 from both sides
\n" ); document.write( "\"64+-+14sqrt%28x%5E2%2B64%29+%2B+49+=+-+18x+%2B+145\"
\n" ); document.write( "\"-14sqrt%28x%5E2%2B64%29+%2B+113+=+-+18x+%2B+145\"
\n" ); document.write( "\"-14sqrt%28x%5E2%2B64%29+=+-+18x+%2B+145+-+113\"
\n" ); document.write( "\"-14sqrt%28x%5E2%2B64%29+=+-18x+%2B+32\"
\n" ); document.write( "simplify, change the signs, divide by -2
\n" ); document.write( "\"7sqrt%28x%5E2%2B64%29+=+9x+-+16\"
\n" ); document.write( "square both sides
\n" ); document.write( "49(x^2 + 64) = 81x^2 - 288x + 256
\n" ); document.write( "49x^2 + 3136 = 81x^2 - 288x + 256
\n" ); document.write( "combine like terms on the right
\n" ); document.write( "0 = 81x^2 - 49x^2 - 288x + 256 - 3136
\n" ); document.write( "0 = 32x^2 - 288x - 2880
\n" ); document.write( "simplify divide by 32
\n" ); document.write( "x^2 - 9x - 90 = 0
\n" ); document.write( "Factors to
\n" ); document.write( "(x-15)(x+6) =
\n" ); document.write( "the positive solution here
\n" ); document.write( "x = 15 in is the altitude of the taller cone
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "See if that checks out the height of the smaller will be 6
\n" ); document.write( "\"sqrt%2815%5E2%2B8%5E2%29\" = 17
\n" ); document.write( "\"sqrt%286%5E2%2B8%5E2%29\" = 10
\n" ); document.write( "----------------------
\n" ); document.write( "slant differences 7 in
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