document.write( "Question 758661: the vertices of a triangle ABC are A(2,1) and B(6,-1) and C(4,11).find the equation of altitude through A of triangle ABC
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Algebra.Com's Answer #461605 by Cromlix(4381)\"\" \"About 
You can put this solution on YOUR website!
Find the gradient of BC
\n" ); document.write( "Formula: y2 - y1/x2 - x1
\n" ); document.write( " 11-(-1)/4 - 6
\n" ); document.write( " 12/-2
\n" ); document.write( " -6
\n" ); document.write( "As an altitude is at right angles
\n" ); document.write( "to the line it emerges from, the
\n" ); document.write( "gradient of the line BC and the
\n" ); document.write( "gradient of the altitude will
\n" ); document.write( "multiply together to give -1
\n" ); document.write( " m1 x m2 = -1
\n" ); document.write( "So, if the gradient of BC is -6
\n" ); document.write( "then the gradient of the altitude
\n" ); document.write( "is 1/6.
\n" ); document.write( "Setting up the equation:
\n" ); document.write( "Using y - b = m(x - a) with m = 1/6 Coords of A (2,1)
\n" ); document.write( " y - 1 = 1/6(x - 2)
\n" ); document.write( " y - 1 = 1/6x - 2/6
\n" ); document.write( " y = 1/6x - 2/6 + 6/6 (1)
\n" ); document.write( " y = 1/6x + 4/6
\n" ); document.write( "This is the equation but you can
\n" ); document.write( "multiply through by 6\r
\n" ); document.write( "\n" ); document.write( " 6y = x + 4
\n" ); document.write( "Hope this helps.
\n" ); document.write( ":-)
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