If you are a believer, then God did but if you are not, then nobody did. The radius of the earth existed and therefore ots radius did before there was any form of life on earth to invent it.
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Approximately 6400km.Diametre between poles is about 12713km.
The radius of the earth is 6400 km.The total surface area is 4*pi*radius square
The radius at the equator is 3,963 miles. It's slightly less through the poles.
The equatorial radius 3,396.2 kilometers (2,110miles).The equatorial circumference of Mars is 21,339 kilometers (13,259 miles).Compared to Earth, the ratio is .533, i.e. the radius and circumference of Mars is about half the radius and circumference of Earth.
with a big tape measure