public double slopeTo(Point that)
	{
		double x0 = this.x;
		double y0 = this.y;
		double x1 = that.x;
		double y1 = that.y;
		
		if (x0 == x1 && y0 == y1)
		{
			return -1.0/0.0;
		}
		else if (y0 == y1)
		{
			return 0;
		}
		else if (x0 == x1)
		{
			return 1.0/0.0;
		}
		else
		{
			return (y1-y0)/(x1-x0);
		}
		/* YOUR CODE HERE */
	}