What would be the radius of the ball representing moon if radius of earth and moon are 6368 km and 1738 km respectively? David Beckham wants to build a model of the Solar system. If he decided that the earth would be represented by a regulation sized soccer ball (roughly spherical and approximately 11 cm radius).



The sizes should be in proportion to each other.

So if 6378 km (i.e 637800000 cm) radius Earth is taken as 11cm radius football, 

then the size of the moon model, let it be x, should be in same proportion.

So 11/637800000=x/173800000

∴x= 11/637800000 * 173800000= 2.9974913766070868610849796174349= 3cm

So size of moon should be approximately taken as 3cm