document.write( "Question 113923: Hi. How would I use the distance, midpoint and slope formula to find where a point should go to make a parallelogram? Because on this homework it shows point A(7,12) B(15,4) C(9,2) D(3,5) The question is to move Point B so that it makes a parallelogram. How would I know where to move it? Thank You for your help! \n" ); document.write( "
Algebra.Com's Answer #82912 by stanbon(75887)\"\" \"About 
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How would I use the distance, midpoint and slope formula to find where a point should go to make a parallelogram? Because on this homework it shows point A(7,12) B(15,4) C(9,2) D(3,5) The question is to move Point B so that it makes a parallelogram. How would I know where to move it? Thank You for your help!
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\n" ); document.write( "Plot the points A, C, and D.
\n" ); document.write( "AB has to be parallel to DC.
\n" ); document.write( "The slope of DC = (2-5)/(9-3) = -3/6 = -1/2
\n" ); document.write( "So the slope of AB as to be -1/2.
\n" ); document.write( "AB also has to pass thru A(7,12)
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\n" ); document.write( "Line AB has the form y=mx+b where y = 12 when x=7, and m = -1/2
\n" ); document.write( "12 = (-1/2)7 + b
\n" ); document.write( "b = 24/2 +7/2 = 31/2
\n" ); document.write( "AB has equation y = (-1/2)x+31/2
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\n" ); document.write( "Line AD has slope (12-5)/(7-3) = 7/4
\n" ); document.write( "Line CB must has the same slope and must pass thru C(9,2)
\n" ); document.write( "2 = (7/4)9 + b
\n" ); document.write( "b = 8/4 -63/4 = -55/4
\n" ); document.write( "CB has equation y = (7/4)x-55/4
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\n" ); document.write( "B is at the intersection of AB and CB.
\n" ); document.write( "(-1/2)x + (31/2) = (7/4)x-(55/4)
\n" ); document.write( "(9/4)x = 117/4
\n" ); document.write( "x = 13
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\n" ); document.write( "Substitute into y = (-1/2)x+31/2 to solve for y:
\n" ); document.write( "y = (-1/2)(13)+(31/2)
\n" ); document.write( "y = -13/2 + 31/2
\n" ); document.write( "y = 9
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\n" ); document.write( "Coordinates of B need to be (13,9)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.\r
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