document.write( "Question 1063014: area of the quadrilateral formed by (2,-1),(4,3),(-1,2),(-3,-2)is \n" ); document.write( "

Algebra.Com's Answer #678050 by Alan3354(69443) $\"\"$ $\"About$

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area of the quadrilateral formed by (2,-1),(4,3),(-1,2),(-3,-2)is
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\n" ); document.write( "Label the points A(2,-1), B(4,3), C(-1,2), D(-3,-2)
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document.write( "A    B    C    D    A\r\n" );
document.write( "2    4   -1   -3    2    --- x values\r\n" );
document.write( "-1   3    2   -2   -1    --- y values\r\n" );
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\n" ); document.write( "Add the diagonal products starting at the upper left:
\n" ); document.write( "= 2*3 + 4*2 + -1*-2 + -3*-1 = 6 + 8 + 2 + 3 = 19
\n" ); document.write( "Add the diagonal products starting at the lower left:
\n" ); document.write( "= -1*4 + 3*-1 + 2*-3 + -2*2 = -4 -3 -6 -4 = -19
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\n" ); document.write( "The difference = 38
\n" ); document.write( "The area = 1/2 the absolute value of the difference
\n" ); document.write( "Area = 19 sq units.
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