document.write( "Question 934543: Twenty five points no three of which are collinear are given in the plane.
\n" ); document.write( "A) How many straight lines do they determine?
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Algebra.Com's Answer #567747 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Suppose the points are labeled with the letters A,B,C,...,Y\r\n" );
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document.write( "(A) A straight line is determined by two points.  There are C(25,2) choices of\r\n" );
document.write( "pairs of those 25 letters.  That's \"%2825%2A24%29%2F%282%2A1%29\" = 300 straight lines.\r\n" );
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document.write( "(B) A triangle is determined by three points which are not collinear.  There are\r\n" );
document.write( "C(25,3) choices of groups of 3 of those 25 letters.  That's \"%2825%2A24%2A23%29%2F%283%2A2%2A1%29\" = 2300 triangles.\r\n" );
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document.write( "Edwin
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