$4$ Somewhere between the Earth and the moon is a point where the gravitational attraction of the Earth is canceled by the gravitational pull of the moon. The mass of the moon is $1/81$ that of the Earth. How far from the center of the earth is this point. $($a$)8/9$ the way to the moon $($b$)9/10$ the way to the moon $($c$)$ the way to the moon $($d$)80/81$ the way to the moon