It is the planet's diameter multiplied by pi
The circumference of a planet is the distance round their widest part. On earth, it is measured round the equator.
The perimeter of a circle
They are circumferences
An arc
The answers depend on what you want to "do" and what information you have.
They are its circumferences
Only one.
d = 9.55 cm
First you times 3.14 by the diameter and there you go
The ratio of all lengths is the same. The ratio of the circumferences = ratio of the radii = 2:3
because its used to calculate areas of circle, circumferences and so on
whats the circumferences of r=8