document.write( "Question 159183: My math teacher has asked me to find the n^th term for the fourth diagonal in Pascal's Triangle. Basicly, he has asked me to find a formula that will find the next number for the fourth diagonal. I've tried all sorts of charts to derieve a formula but none have yeilded any. \n" ); document.write( "
Algebra.Com's Answer #117306 by gonzo(654)\"\" \"About 
You can put this solution on YOUR website!
the equation for the 3d diagonal is given as:
\n" ); document.write( "\"%28%28n%2B1%29%2An%29%2F2\"
\n" ); document.write( "the equation for the 4th diagonal is given as:
\n" ); document.write( "\"%28%28n%2B2%29%2A%28n%2B1%29%2A%28n%29%29%2F6\"
\n" ); document.write( "-----------------------------------------
\n" ); document.write( "try these websites.
\n" ); document.write( "the first one describes pascal's triangle.
\n" ); document.write( "the second one actually give you equations to calculat the nth term.
\n" ); document.write( "-------------------------------------------
\n" ); document.write( "the first website is: http://www.mathsisfun.com/tetrahedral-number.html
\n" ); document.write( "the second website is: http://noticingnumbers.net/220PASCALStriangle.htm
\n" ); document.write( "-----------------------------------------
\n" ); document.write( "the formulas i provided you are taken from the second website and manipulated so the manual calculations are easier.
\n" ); document.write( "-------------------------------------------
\n" ); document.write( "a test of the formulas for the 9th term is constructed below.
\n" ); document.write( "the answer should be 45 for the 3d diagonal and 165 for the 4th diagonal.
\n" ); document.write( "--------------------------------------------
\n" ); document.write( "for the 3d diagonal, the formula for the 9th term (n = 9) yields
\n" ); document.write( "(10*9)/2 which equals 90/2 which equals 45 which is correct.
\n" ); document.write( "---------------------------------------------
\n" ); document.write( "for the 4th diagonal, the formula for the 9th term (n = 9) yields
\n" ); document.write( "(11*10*9)/6 = 990/6 = 165.
\n" ); document.write( "----------------------------------------------
\n" ); document.write( "these formulas actually work !!!!!
\n" ); document.write( "hopefully this is what you were looking for.\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );