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Math Help - Given Points

  1. #1
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    Post Given Points

    Given points C (4,3) and D (2,-5), find the slope of every line parallel to Line CD.

    Given points R (-2,3) and S (5,1), find the slope of every line perpendicular to Line RS.

    A. slope of Line RS

    B. slope of perpendicular lines
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  2. #2
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    Given points C (4,3) and D (2,-5), find the slope of every line parallel to Line CD.

    (2,-5) (4,3)

    Use the gradient formula.
    y2-y1 / x2-x1

    3 - (-5) / 4 - 2
    8 / 2
    Slope = 4

    When lines are parallel, they all have the same slope, therefore the slope of every line parallel to CD = 4


    -------

    Given points R (-2,3) and S (5,1), find the slope of every line perpendicular to Line RS.

    Again, gradient formula gives
    -2/3

    For any line perpendicular. The gradient changes.
    In general, all you do is "flip" the gradient (-2/3) upside down so it becomes (-3/2). Then you multiply the new gradient by -1.
    Every line perpendicular to RS will therefore be 3/2

    For example if you don't get me.
    A line has slope of -1/2.
    Perpendicular lines to that line will be 2.
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  3. #3
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    Soo -2/3 ==> -3/2*-1= 3/2 ?

    Soo..1.5 is the answer?

    Is that correct?
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  4. #4
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    Yes
    3/2 is the gradient of the line perpendicular to RS.
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