What the equation?

Answer 1

The equator is an imaginary line halfway between the North Pole and the South Pole.
The equator is the most important line of latitude goes round the world at its widest point

is 40,075 km long & divides the world into southern & northern hemisphere.

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Answer #2:

Find a point on your globe that's equal distances from the north and south poles,

and make a tiny mark there. Then find another point that's equal distances from

the north and south poles, and make another tiny mark there. Then do the same

thing at twenty, fifty, or a thousand more points. After a while, all those points

start to blend together and look like a solid line, with every point on the line being

equal distances from the north and south poles. That line is the Equator.