The magnitude of the gravitational force acting on an object, F, is proportional to the universal gravitational constant, G, and the product of the two masses involved, m and M. It is inversely proportional to the distance between the objects, r, squared.
This magnitude is otherwise stated as F = G(Mm/r?). If either of the object's masses increase or the distance between them decreases, the magnitude of the force increases. If the masses decrease or the distance increases, the magnitude decreases. The direction of the force of gravity lies along a straight line connecting the center of masses of both objects.