CODEWITHSUNDEEP
rubymathtrigonometry
fabriciofreitag
fabriciofreitag

Reputation: 2883

Triangle coordinates calculation

I converted the code from this post to ruby, just added some code for the triangle orientation, which works on 95% percent of the cases.

def find_triangle_coordinates(point_a, point_b, ac_length, bc_length, orientation)
  if orientation == :down
    temp = point_a
    point_a = point_b
    point_b = temp
  end

  ab_length = distance(point_a, point_b)
  ad_length = (ab_length**2 + ac_length**2 - bc_length**2) / (2.0 * ab_length)

  h = sqrt((ac_length**2 - ad_length**2).abs)

  d_x = point_a.x + ad_length * (point_b.x - point_a.x) / ab_length
  d_y = point_a.y + ad_length * (point_b.y - point_a.y) / ab_length

  point_d = Point(d_x, d_y)

  c_x1 = point_d.x + h * (point_b.y - point_a.y) / ab_length
  c_x2 = point_d.x - h * (point_b.y - point_a.y) / ab_length
  c_y1 = point_d.y - h * (point_b.x - point_a.x) / ab_length
  c_y2 = point_d.y + h * (point_b.x - point_a.x) / ab_length

  if orientation == :down
    Point(c_x1, c_y1)
  else
    Point(c_x2, c_y2)
  end

But when I pass the following parameters:

find_triangle_coordinates(Point(0, 0), Point(539.939, 0), 130.0, 673.746, :down)

The output it's giving me this triangle:

output

Which is slightly bigger than the expected. Anyone knows why? Also, any other approaches to solve the same problem are welcome. Thanks!!

Upvotes: 2

Views: 264

Answers (1)

jkeuhlen
jkeuhlen

Reputation: 4517

Your input lengths cannot form a triangle.

The sum of the lengths of any two sides of a triangle must be greater than the length of the third side of that triangle.

539.939 + 130.0 = 669.939 which is less than the third side of length 673.746

So your code seems to be trying to fit those lengths to a triangle, which requires a bit of elongation.

Upvotes: 4

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