You weigh 730 n. what would you weigh if the earth were six times as massive as it is and its radius were three times its present value? answer in units of n.

By definition we have to:
 F = G * M * m / r ^ 2
 where,
 F = Gravitational force
 G = Gravitational constant. (6.67 x 10 ^ -11 Nm ^ 2 / kg ^ 2)
 M = mass of the earth
 m = mass of the object
 r = radius of the earth
 If the earth were six times as massive as it is:
 M = 6M
 radius were three times its present value:
 r = 3r
 We have the equation is:
 F = G * (6M) * m / (3r) ^ 2 = (6/9) * (G * M * m / r ^ 2) = (2/3) * (G * M * m / r ^ 2 )
 Therefore the weight will be
 (2/3) * F = (2/3) * (730) = 487N
 answer
 Your weight will be 487N