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) You can put this solution on YOUR website! formula for volume of a sphere is:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "formula for surface area of a sphere is:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if we solve for r in the equation for the volume of the sphere, we get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "take the cube root of both sides of this equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \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 \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if we double v, then this equation becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if we divide s[2] by s[1] we get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this simplifies to:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "multiply both sides of this equation by \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "for example:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "let the volume of the sphere be equal to 300.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we solve for the radius to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "radius of the sphere equals 4.152830592\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we confirm by substituting in the equation for the volume of the sphere to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "v = 4/3 * pi * (4.152830592)^3 = 300 cubic units.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the surface area of the sphere is equal to 4 * pi * r^2 = 216.7196518 square units.\r \n" ); document.write( " \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 * \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "to confirm this is correct, we need to solve for the radius of the new sphere.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the volume of the new sphere is equal to 600 cubic units.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the radius of the new sphere is calculated to be 5.23223868 units.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the surface area of the new sphere is equal to 4 * pi * r^2 which becomes\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since this is the same as \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the answer to your question is:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the surface area was multiplied by \n" ); document.write( " \n" ); document.write( " |