document.write( "Question 262877: Suppose you wish to reduce the volume of a sphere by a factor of 7.00. If it's original radius was R, what is the reduced radius in terms of R? By what factor does the sphere's surface area change?
\n" ); document.write( "I have no idea how to even approach this. I'm assuming that the answers to both the questions will have 7's in them.
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Algebra.Com's Answer #193656 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
The formula for the volume of a sphere is
\n" ); document.write( "(1)\"V+=+%284%2F3%29%2Api%2AR%5E3\"
\n" ); document.write( "Making the sphere seven times smaller means
\n" ); document.write( "multiplying \"V\" by \"1%2F7\"
\n" ); document.write( "Let \"R%5B2%5D\" = the new radius when \"V\"
\n" ); document.write( "is \"1%2F7\" of what it used to be
\n" ); document.write( "(2) \"%281%2F7%29%2AV+=+%284%2F3%29%2Api%2A%28R%5B2%5D%29%5E3\"
\n" ); document.write( "Now I need to find \"R%5B2%5D\" in terms of \"R\"
\n" ); document.write( "Multiply both sides of (1) by \"21\"
\n" ); document.write( "(2) \"3V+=+28%2Api%2A%28R%5B2%5D%29%5E3\"
\n" ); document.write( "(2) \"%28R%5B2%5D%29%5E3+=+%283V%29%2F%2828%2Api%29\"
\n" ); document.write( "Now I need to substitute \"V\" in (1) for \"V\" in (2)
\n" ); document.write( "(2) \"%28R%5B2%5D%29%5E3+=+%283%2A%284%2F3%29%2Api%2AR%5E3%29%2F%2828%2Api%29\"
\n" ); document.write( "(2) \"%28R%5B2%5D%29%5E3+=+%281%2F7%29%2AR%5E3\"
\n" ); document.write( "Now take the cube root of both sides
\n" ); document.write( "(2) \"R%5B2%5D+=+%281%2F7%29%5E%281%2F3%29%2AR\"
\n" ); document.write( "\"R%5B2%5D\" is the reduced radius in terms of \"R\"
\n" ); document.write( "The surface areas are proportional to \"R%5E2\" and \"%28R%5B2%5D%29%5E2\"
\n" ); document.write( "Because \"A+=+4%2Api%2AR%5E2\"
\n" ); document.write( "so I can rewrite (2) as
\n" ); document.write( "(2) \"R%5B2%5D+=+%281%2F7%29%5E%281%2F3%29%2AR\"
\n" ); document.write( "(2) \"%28R%5B2%5D%29%2FR+=+%281%2F7%29%5E%281%2F3%29\"
\n" ); document.write( "Now square both sides
\n" ); document.write( "\"%28R%5B2%5D%29%5E2%2F%28R%5E2%29+=+%28%281%2F7%29%5E%281%2F3%29%29%5E2\"
\n" ); document.write( "\"%28R%5B2%5D%29%5E2%2F%28R%5E2%29+=+%281%2F7%29%5E%282%2F3%29\"
\n" ); document.write( "This is the factor that the surface area changes by\r
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