document.write( "Question 251474: We just blew some air into a spherical balloon and doubled its volume. By how much did we multiply the surface area ? \n" ); document.write( "
Algebra.Com's Answer #183144 by Theo(13342)\"\" \"About 
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formula for volume of a sphere is:\r
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\n" ); document.write( "\n" ); document.write( "\"v%5B1%5D+=+4%2F3+%2A+pi+%2A+r%5E3\"\r
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\n" ); document.write( "\n" ); document.write( "formula for surface area of a sphere is:\r
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\n" ); document.write( "\n" ); document.write( "\"s%5B1%5D+=+4+%2A+pi+%2A+r%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "if we solve for r in the equation for the volume of the sphere, we get:\r
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\n" ); document.write( "\n" ); document.write( "\"r%5E3+=+%283%2Av%29%2F%284%2Api%29\"\r
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\n" ); document.write( "\n" ); document.write( "take the cube root of both sides of this equation to get:\r
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\n" ); document.write( "\n" ); document.write( "\"r+=+%28%283%2Av%29%2F%284%2Api%29%29%5E%281%2F3%29\"\r
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\n" ); document.write( "\n" ); document.write( "if substitute for the value of r in the equation for the surface area of the sphere, then we get:\r
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\n" ); document.write( "\n" ); document.write( "\"s%5B1%5D+=+4+%2A+pi+%2A+r%5E2\" becomes:\r
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\n" ); document.write( "\n" ); document.write( "\"s%5B1%5D+=+4+%2A+pi+%2A+%28%28%283%2Av%29%2F%284%2Api%29%29%5E%281%2F3%29%29%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "if we double v, then this equation becomes:\r
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\n" ); document.write( "\n" ); document.write( "\"s%5B2%5D+=+4+%2A+pi+%2A+%28%28%286%2Av%29%2F%284%2Api%29%29%5E%281%2F3%29%29%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "if we divide s[2] by s[1] we get:\r
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\n" ); document.write( "\n" ); document.write( "this simplifies to:\r
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\n" ); document.write( "\n" ); document.write( "\"s%5B2%5D%2Fs%5B1%5D+=+2%5E%282%2F3%29\" which is the same as:\r
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\n" ); document.write( "\n" ); document.write( "\"s%5B2%5D%2Fs%5B1%5D+=+root%283%2C2%29%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "multiply both sides of this equation by \"s%5B1%5D\" and you get:\r
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\n" ); document.write( "\n" ); document.write( "\"s%5B2%5D+=+root%283%2C2%29%5E2%2As%5B1%5D\"\r
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\n" ); document.write( "\n" ); document.write( "for example:\r
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\n" ); document.write( "\n" ); document.write( "let the volume of the sphere be equal to 300.\r
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\n" ); document.write( "\n" ); document.write( "we solve for the radius to get:\r
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\n" ); document.write( "\n" ); document.write( "radius of the sphere equals 4.152830592\r
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\n" ); document.write( "\n" ); document.write( "we confirm by substituting in the equation for the volume of the sphere to get:\r
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\n" ); document.write( "\n" ); document.write( "v = 4/3 * pi * (4.152830592)^3 = 300 cubic units.\r
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\n" ); document.write( "\n" ); document.write( "the surface area of the sphere is equal to 4 * pi * r^2 = 216.7196518 square units.\r
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\n" ); document.write( "\n" ); document.write( "if the sphere doubles in volume, then the surface area of the new sphere should be equal to 216.7196518 * \"root%283%2C2%29%5E2\" making the surface area of the new sphere equal to\r
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\n" ); document.write( "\n" ); document.write( "\"s%5B2%5D+=+344.0210033\" square units\r
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\n" ); document.write( "\n" ); document.write( "to confirm this is correct, we need to solve for the radius of the new sphere.\r
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\n" ); document.write( "\n" ); document.write( "the volume of the new sphere is equal to 600 cubic units.\r
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\n" ); document.write( "\n" ); document.write( "the radius of the new sphere is calculated to be 5.23223868 units.\r
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\n" ); document.write( "\n" ); document.write( "the surface area of the new sphere is equal to 4 * pi * r^2 which becomes\r
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\n" ); document.write( "\n" ); document.write( "\"s%5B2%5D+=+4+%2A+pi+%2A+%285.23223868%29%5E2+=+344.0210033\"\r
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\n" ); document.write( "\n" ); document.write( "since this is the same as \"216.7196518+%2A+root%283%2C2%29%5E2\" then we're good.\r
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\n" ); document.write( "\n" ); document.write( "the answer to your question is:\r
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\n" ); document.write( "\n" ); document.write( "the surface area was multiplied by \"root%283%2C2%29%5E2\".
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