How to compute Distance from pixel size

[hikme]

I can compute the pixel size at a distance from the View.
pixelScale = view.computePixelSizeAtDistance(view.com puteHorizonDistance());
I can display the pixel size just calculated as my scale when the zoom value change i compute the new pixel size(Scale). Is their a way i can compute the distance for a given pixel size. Allow the user to change pixel size (scale) then i compute the distance and change the zoom to display the globe at the new scale(pixel size).
Thanks