Find third vertex of Triangle when two Vertices are given

Get Third vertex of triangle


Let us suppose that we have two vertex a(x,y) and b(x1,y1) then

just pass two points to below given function and it will return C(X,Y) i.e. third vertex.

function getPointC(a, b)
{
     var pivotPoint;

     if (b.x > a.x)
     {
            pivotPoint = a;
     }
    else
    {
        pivotPoint = b; 
    }

    var dx = b.x - a.x;
    var dy = b.y - a.y;

    var lengthAB = Math.sqrt(Math.pow(dx, 2) + Math.pow(dy, 2));    
    var angleAB = Math.atan(dy/dx); 

    var c = new Object();

    c.x = lengthAB*Math.cos(angleAB + 60*Math.PI/180) + pivotPoint.x;
    c.y = lengthAB*Math.sin(angleAB + 60*Math.PI/180) + pivotPoint.y;

    return c;   
}