document.write( "Question 33574: Hi. My problem is:\r
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Algebra.Com's Answer #19975 by AnlytcPhil(1806)\"\" \"About 
You can put this solution on YOUR website!
Hi. My problem is: \r\n" );
document.write( "How many planes are determined by four points, no three of \r\n" );
document.write( "which are collinear? \r\n" );
document.write( "Thanks a lot!\r\n" );
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document.write( "Three noncolinear points determine a plane.\r\n" );
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document.write( "If the points are A, B, C, and D.\r\n" );
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document.write( "1. The three non-colinear points A, B, and C determine a plane.\r\n" );
document.write( "2. The three non-colinear points A, B, and D determine a plane.\r\n" );
document.write( "3. The three non-colinear points A, C, and D determine a plane.\r\n" );
document.write( "4. The three non-colinear points B, C, and D determine a plane.\r\n" );
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document.write( "The answer is four.\r\n" );
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document.write( "You can also do it by the combination of 4 things taken 3 at a time\r\n" );
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document.write( "                  4C3\r\n" );
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document.write( "and using the formula\r\n" );
document.write( "                            n!   \r\n" );
document.write( "                  nCr = ——————————\r\n" );
document.write( "                        r!(n - r)!\r\n" );
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document.write( "                            4!   \r\n" );
document.write( "                  4C3 = ——————————\r\n" );
document.write( "                        3!(4 - 3)!\r\n" );
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document.write( "                          4·3·2·1   \r\n" );
document.write( "                  4C3 = ——————————\r\n" );
document.write( "                        3·2·1·(1)!\r\n" );
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document.write( "                          4·3·2·1   \r\n" );
document.write( "                  4C3 = ——————————\r\n" );
document.write( "                           3·2·1\r\n" );
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document.write( "                  4C3 = 4\r\n" );
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document.write( "Edwin\r\n" );
document.write( "AnlytcPhil@aol.com

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