How to re format GetVertices to return (x1,y1,0), (x2,y2,0), (x3,y3,0);?

Question

So, I have given added a constructor that makes it possible to create triangles with the expression new Triangle(x1, y1, x2, y2, x3, y3) where (x1,y1), (x2,y2), (x3,y3) are the