Question

the radius of earth- 6400 km but how we proved it​

Answer 1

Answer:

Radius of earth = 6400 km =6400 × 1000 m ( 1km = 1000m)

So radius of earth = 6400000m

And radius of Mars = 4300000m

So radius of earth is bigger by 2100000m

Answer 2

Answer:

Using Newton's Law of Gravition (earlier) later using Space sattelites and General Theory of Relativity

Explanation:

g varies with height so measuring g at two heights will give us R however there might be better ways to prove that