The ratio of their diameters and radii is 1 : 4. Since the surface area of a sphere is proportional to the square of its radius, the ratio of their surface areas is 1² : 4² = 1 : 16.
Cbse Class 9 Maths Ganita Manjari Part 2 Solutions
Class 9 maths ganita manjari part 2 chapter 14 question answer
Let the diameter of the Earth be D and the diameter of the Moon be D/4, meaning their radii are in the ratio r_moon / r_earth = 1 / 4. The surface area of a sphere is given by SA = 4πr². Therefore, the ratio of their surface areas is SA_moon / SA_earth = (r_moon / r_earth)² = (1/4)² = 1 / 16, which is 1 : 16.
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