The area of the ellipse is simply pi times the multiplication of the two axes:

Area = pi*(Rx-x)*(Ry-y).

I don't know what you mean by start or end angle and total length of ellipse, but I am assuming you are referring to the angletformed the by the line from the center to the circumference. Then the perimeter of the ellipse is:

4*(Rx-x)*INTEGRAL_{0 to pi/2}[sqrt(1-((Rx-x)^2-(Ry-y)^2)/(Rx-x)^2 * sin(t))* dt].