Question

The diameter of the moon is approx.  One-fourth the diameter of the earth. Find the ratio of their surface area. 

Answer 1

first of all..it is one-sixth.
ratio of surface are of moon/earth=4*$\pi$*$radius of moon^{2}$ /4*$\pi$*$radius of earth^{2}$............in question radius of earth would be given.so just input the values.

Answer 2

let diameter of moon=d
⇒radius of moon=d/2=r
⇒diameter of earth=D
since, d is 1/4 D
⇒D=4d=diameter of earth
radius of earth,R=D/2=4d/2
⇒R=4×2r÷2 = 4r
ratio of surface areas=surfacearea of moon : surfacearea of earth
   =4πr² : 4πR²
   =r² : (4r)²
   =r² : 16r²
⇒ ratio1:16