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Math Help - point inside an area

  1. #1
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    point inside an area

    hi, im using excel to calculate if a plane is within limits (cog) and im nearly finished. Im trying to set a warning for when it goes outside limits, represented on a graph, i need a formula to find if a point is within a givin area, i have the points of the area say, A,B,C,D it is not a perfect square or a rectangle. so if anyone can help i would greatly appreciate it.
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  2. #2
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    Quote Originally Posted by jazzmcd View Post
    i have the points of the area say, A,B,C,D it is not a perfect square or a rectangle.
    Well, what's given? In this case, the coordinates of A, B, C and D?
    Your question is too "general".
    As a start, google "point inside triangle".
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  3. #3
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    its not a triangle it has 6 points, i know the co-ordinates of each, and have 5 points that make up a line that are to be plotted, for each of those plotted points i need a formula to find if those points are in the area of the 6-pointed shape, i have co-ordinates of all points mentioned.
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  4. #4
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    Quote Originally Posted by jazzmcd View Post
    its not a triangle it has 6 points, i know the co-ordinates of each, and have 5 points that make up a line that are to be plotted, for each of those plotted points i need a formula to find if those points are in the area of the 6-pointed shape, i have co-ordinates of all points mentioned.
    6 points usually result in a hexagon; many weird shapes possible; see here:
    Hexagon - Wikipedia, the free encyclopedia

    But not always a hexagon; like, if 3 points are collinear, you end up with a pentagon;
    but I guess that's beside the point...

    All to say that I don't know! I'll guarantee it won't be something simple

    On the positive side, there are geometrical whizzes here: perhaps they'll step in
    and save the day
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  5. #5
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    point inside an area-cog.jpg
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  6. #6
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    Well, if it restricted to a convex hexagon (as your diagram seems to indicate),
    then perhaps the way to go is divide the hexagon in 4 triangles (easy enough),
    then check if each point is inside one of these triangles...Oh Archie, where art thou?!
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