I can't readily recall the Earth's actual sq. km surface area, and can't remember ever having heard the figure for Mars. Time to drop into Wikipedia and take a gander, I think.

EDIT: I'll be damned, TIL that the Earth has an area of 510.06 10^6 km², but Mars' is only 144.37 10^6 km², only about 1⁄3 the size (28.3%).

[–] JackbyDev@programming.dev 10 points 6 days ago* (last edited 5 days ago) (1 children)

The circumference is roughly 40,000 kilometers. The original definition for a meter was such that 10,000 kilometers was the distance from the equator to the poles (so a quarter of the circumference). They got the math slightly wrong and didn't want to people to think the process was wrong so they didn't correct it. I forget the actual circumference but that is close enough for very rough estimates.

[–] dragonfucker@lemmy.nz 5 points 6 days ago (1 children)

the distance from the equator to the poles is a quarter of the circumference

[–] JackbyDev@programming.dev 2 points 5 days ago

Yeah idk why I got circumference and diameter mixed up. Whoops.

[–] jnod4@lemmy.ca 2 points 6 days ago

Pebble