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Math Help - coordinates that trisect a line segment

  1. #1
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    coordinates that trisect a line segment

    this question I don't have much work to show. :

    IF A is (3,6,8) and B is (6,0,-1). Find the points that trisect the line segment.

    I thought I would do A+B(1/3) and A+B(2/3) didn't work correctly though. the correct answer is (4,4,5) and (5,2,2).

    Thanks in advance
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  2. #2
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    Quote Originally Posted by colorado View Post
    this question I don't have much work to show. :

    IF A is (3,6,8) and B is (6,0,-1). Find the points that trisect the line segment.

    I thought I would do A+B(1/3) and A+B(2/3) didn't work correctly though. the correct answer is (4,4,5) and (5,2,2).

    Thanks in advance
    note the distance between the x-coordinates is 3 ... so, the x-coordinates for the other two points have to trisect this component length of 3. 3/3 = 1 ... the x-coordinates must be 4 and 5.

    do the same for the y and z coordinates.

    y-coordinates will be 6/3 = 2 units apart

    z-coordinates will be 9/3 = 3 units apart
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  3. #3
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    Quote Originally Posted by colorado View Post
    I thought I would do A+B(1/3) and A+B(2/3)
    Right idea, but not accurate. You should have gone for A + (1/3)(B–A) and A + (2/3)(B–A).
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