document.write( "Question 1066281: Find 3 numbers in the geometrical progression whose sum is 28 and whose product is 512 \n" ); document.write( "

Algebra.Com's Answer #681629 by ikleyn(52866) $\"\"$ $\"About$

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\n" ); document.write( "Find 3 numbers in the $\"highlight%28cross%28geometrical%29%29\"$ geometric progression whose sum is 28 and whose product is 512
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document.write( "Let the middle term be \"x\" and the common ratio be r.\r\n" );
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document.write( "Then the first of the three terms is , and the third term is .\r\n" );
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document.write( "The product of the three terms is  = .\r\n" );
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document.write( "Thus  = 512, which implies x = 8.\r\n" );
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document.write( "So, you just found the middle term. It is 8.\r\n" );
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document.write( "Then the sum of the three terms is  = 28, which gives you an equation\r\n" );
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document.write( " = 28 - 8,   or   = 28 - 8 = 20,   or    = ,   or   =  = 2.5\r\n" );
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document.write( "which has the roots  r = 2  and/or  r= .\r\n" );
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document.write( "Thus the progression is  {4, 8, 16}   or   {16, 8, 4}.\r\n" );
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