1

Hello I am trying to write a java program that takes three points (a,b, and c) and finds the area of a triangle. I am getting stuck because I don't know the coordinates of the points (they will be given later in a tester class). Should i write the code to convert the points to cartesian coordinates and then use those to find the area? Im really stuck on this so any suggestions will help. Thanks.

J.Daniels
  • 77
  • 10
  • 1
    "Should i write the code to convert the points to cartesian coordinates" What in your view is the difference between a point and cartesian coordinates? – weston Jan 25 '16 at 08:11
  • @weston the points I have are Point a, Point b, Point C. I don't know how to convert this to say (Ax,Ay),(Bx,By). Does that make sense? – J.Daniels Jan 25 '16 at 16:16
  • @Tim thank you, thats exactly what I was looking for! – J.Daniels Jan 25 '16 at 16:18
  • No it makes no sense to convert as a point already has X and Y parts. – weston Jan 25 '16 at 22:52

1 Answers1

2

A compact and nicely symmetric way to remember the area formula is

              [ 1 a.x a.y ]
area = 0.5*det[ 1 b.x b.y ]
              [ 1 c.x c.y ]

This will give a signed area, negative if the order of the vertices is clockwise. For implementations one of course simplifies the determinant by row and column operations.

Lutz Lehmann
  • 25,219
  • 2
  • 22
  • 51