Feb 23, 2010

Get Triangle Height in JavaScript

How to find the height of a triangle in JavaScript if you only have the 3 vertexes/points of the triangle.

Assuming that XY are the top of your triangle, and X1Y1, X2Y2 are the other two points, you can find the height of the triangle using Pythagorean theorem. This method works for Isosceles or Equilateral triangles.

  // Pythagorean theorem for isosceles or equilateral triangle 
  var getTriangleHeight = function(x, y, x1, y1, x2, y2){
    var b = Math.sqrt(Math.pow(x2-x1, 2) + Math.pow(y2-y1, 2)) /2;
    var c = Math.sqrt(Math.pow(x1-x,  2) + Math.pow(y1-y,  2));    
    return Math.sqrt((c*c)-(b*b));
  };

This entry was posted by Al MacDonald on February 23, 2010 in JavaScript.