Given a planet of the same (relative) density as Earth, and a G-force on said planet of 1.916G, what is the procedure to determine the radius and surface area for such a planet, given it having only 57% water coverage? I will admit that I am working on this for a book series I started in 2002, but my initial calculations obtained a ridiculously large planet size (17x Earth's surface area). Clearly, my own efforts were (at the time) incorrect equations, but I will admit that my math skills may not be up to the task, although much of the data I originally based the calculations on have been lost. Other planets in my series are Earth-type, albeit different due to the stars they orbit being far different from our Sun. I want to ultimately be able to explain why such a planet would have a rotational period of 100,000 seconds, and an orbital period of 1,000 of those rotations (roughly 3.17 Terran years), yet be habitable. Bear in mind that I am not requesting that someone do the work, just help me obtain the knowledge needed to do the work myself for this project.