How is the acceleration due to gravity on the surface of the earth related to it’s mass and radius ?

By newton’s law of motion, the force due to gravity on a body of mass m on it’s surface will be

F = mass × acceleration due to gravity

or F = mg     [Equation 1]

By Newton’s gravitational law, this attractive force is given by

F =  {GMm\over R^2} [Equation 2]

From eqn. 1 and 2 we get,

mg = {GMm\over R^2}

⇒ acceleration due to gravity g = {GM\over R^2}