Algebra.Com's Answer #61596 by Edwin McCravy(20056)  You can put this solution on YOUR website! I really need help with this one, can someone please help me\r \n" );
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document.write( "Use coordinate geometry to prove that the quadrilateral OPQR \n" );
document.write( "with vertices O(0,0),P(9,3),Q(9,8), and R(-3,4) is an isosceles \n" );
document.write( "trapezoid. \n" );
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document.write( "We have to show that OP II QR, i.e., that both\r\n" );
document.write( "have the same slope. \r\n" );
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document.write( "mOP = = = \r\n" );
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document.write( "mQR = = = \r\n" );
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document.write( "Their slopes are equal, so OPQR is either a trapezoid or a parallelogram.\r\n" );
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document.write( "Now let's show that PQ = RO\r\n" );
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document.write( "DPQ = = = = = \r\n" );
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document.write( "DRO = = = = = \r\n" );
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document.write( "You might think this is enough to show that that OPQR is an isosceles\r\n" );
document.write( "trapezoid since one pair of opposite sides are parallel and the other \r\n" );
document.write( "pair of opposite sides are equal in length.\r\n" );
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document.write( "However, that could be said about a rectangle. We must rule out\r\n" );
document.write( "a rectangle. (Yes we can look and see that it's not a rectangle,\r\n" );
document.write( "but \"looking and seeing\" is not acceptable. The easiest way to do \r\n" );
document.write( "this is to rule out a right angle using slopes. We will show that\r\n" );
document.write( "OP is not perpendicular to RO\r\n" );
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document.write( "We have already found the slope of OP as 1/3. So we will rule out\r\n" );
document.write( "OPQR as being a rectangle by showing that the slope of RO is not\r\n" );
document.write( "the \"negative reciprocal\" of 1/3. That is to show that the slope of\r\n" );
document.write( "RO is not -3.\r\n" );
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document.write( "mRO = = = \r\n" );
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document.write( " is not equal to so we have ruled out a rectangle.\r\n" );
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document.write( "So OPQR must be an isosceles trapezoid.\r\n" );
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document.write( "Edwin \r \n" );
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