document.write( "Question 256439: ron was doodling in his notebook and noticed the following: 3 segments can be drawn between 3 points, 6 segments can be drawn between 4 points, and 10 segments can be drawn between 5 points.
\n" ); document.write( "a. find an equation giving the number of segments \"y\" as a function of the number of points \"x\".
\n" ); document.write( "b. according o this formula howmany segments can be drawn between 70 points.
\n" ); document.write( "c. how many points are needed to draw 45 segments between them.
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Algebra.Com's Answer #188648 by drk(1908)\"\" \"About 
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Here the pattern is 1,3,6,10, . . .
\n" ); document.write( "The formula is
\n" ); document.write( "\"Y+=+%28x%2A%28x%2B1%29%29%2F2\"
\n" ); document.write( "where x is the number of points
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\n" ); document.write( "If x = 70, then
\n" ); document.write( "\"Y+=+%2870%2A%2870%2B1%29%29%2F2\" = 2485 segments
\n" ); document.write( "--
\n" ); document.write( "\"45+=+%28x%2A%28x%2B1%29%29%2F2\"
\n" ); document.write( "\"90+=+x%2A%28x%2B1%29\"
\n" ); document.write( "x = 9, x+1 = 10.
\n" ); document.write( "We need 9 points for 45 segments
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