### Higher Help needed -Urgently Please!

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• #### Message 1.

Posted by U15219824 (U15219824) on Tuesday, 8th May 2012

ABCD is a parallelogram whose diagonals intersect at E. If A,B and E are the points (-1,0), (3,-2) and (1,4) respectively, find the equation of DC.

Thank you!

• #### Message 2

, in reply to message 1.

Posted by Maths Teacher BBC (U15178780) on Tuesday, 8th May 2012

If you sketch roughly where the points would be then it is easy to see a rough shape.

The line AB and the line CD are patsllel on a rhombus.
So if you find the gradient of the line AB then CD is the same:

M CD = -1/2

For the point: Use the step it out process:

From point B (3,-2) to point E (1,4) - this is 2 along and 6 up.
Do the same from E (1, 4) - 2 along 6 up takes you to the point (-1,10).

You now have your point and gradient and so equation of a staright line -

y - b = m(x-a)
y - 10 = -1/2 (x - (-2))
y - 10 = -1/2 (x + 2)

And so on.....

• #### Message 3

, in reply to message 2.

Posted by U15219824 (U15219824) on Tuesday, 8th May 2012

Thank you very much for replying so quickly! Have a much clearer idea of what to do with this question!

Thanks again.

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