point1が交点。
var point0:Point, point1:Point, point2:Point; point0 = new Point( 50, 100 ); point1 = new Point( 200, 200 ); point2 = new Point( 100, 300 ); point0.offset( -point1.x, -point1.y ); point2.offset( -point1.x, -point1.y ); var vector0:Vector3D, vector1:Vector3D; vector0 = new Vector3D( point0.x, point0.y, 0 ); vector1 = new Vector3D( point2.x, point2.y, 0 ); var angle:Number = Vector3D.angleBetween( vector0, vector1 ); //このときはまだラジアン var d:Number = angle * 180/Math.PI;
もっと早い書き方があるような気がするが、なんとか算出できた。