document.write( "Question 119374: Quadrilateral ABCD has vertices A(0,-2), B(9,1), C(4,6), and D(1,5). Prove: a) Quadrilateral ABCD is a trapezoid. b) Quadrilateral ABCD is an isosceles trapezoid. \n" ); document.write( "

Algebra.Com's Answer #87528 by Edwin McCravy(20056) $\"\"$ $\"About$

You can put this solution on YOUR website!
Quadrilateral ABCD has vertices A(0,-2), B(9,1), C(4,6), and D(1,5). Prove: a) Quadrilateral ABCD is a trapezoid. b) Quadrilateral ABCD is an isosceles trapezoid.\r
\n" ); document.write( "\n" ); document.write( "

\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "First we prove that AB and DC are parallel, \r\n" );
document.write( "by showing they have the same slope:\r\n" );
document.write( "\r\n" );
document.write( "Slope of AB\r\n" );
document.write( "     \r\n" );
document.write( "m =  =  =  = \r\n" );
document.write( "\r\n" );
document.write( "Slope of DC\r\n" );
document.write( "\r\n" );
document.write( "m =  = \r\n" );
document.write( "\r\n" );
document.write( "There are both  so they are parallel and so ABCD is\r\n" );
document.write( "a trapezoid.\r\n" );
document.write( "\r\n" );
document.write( "To show that it is isosceles, we prove that AD = CB\r\n" );
document.write( "\r\n" );
document.write( "Length of AD\r\n" );
document.write( "\r\n" );
document.write( "d =  =  =  = \r\n" );
document.write( "=  =  =  \r\n" );
document.write( "\r\n" );
document.write( "Length of CB\r\n" );
document.write( "\r\n" );
document.write( "Length of AD\r\n" );
document.write( "\r\n" );
document.write( "d =  =  =  =  =  =  \r\n" );
document.write( "\r\n" );
document.write( "These are both  so it is also isosceles.\r\n" );
document.write( "\r\n" );
document.write( "Edwin

\n" ); document.write( "

\n" );