The Earth's equator is approximately how many thousands of kilometres in length?

In two widely used geodetic standards, the Equator is modelled as a circle whose radius is a whole number of metres. In 1976 the IAU chose a radius of 6,378.140 kilometres (3,963.192 mi), later refined by the IUGG to 6,378.137 kilometres (3,963.191 mi) and adopted in WGS-84, though the yet more recent IAU-2000 has retained the old IAU-1976 value. If it were really circular the length of the Equator would be exactly 2π times the radius, namely 40,075.036 kilometres (24,901.473 mi). However, due to the effect of tidal force on the Earth's surface the actual circumference at the equator is 40,075.16 kilometres (24,901.55 mi).

More Info: en.wikipedia.org

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25 Comments

Brian G

Fred Keogh, reverse that - kilometers are shorter: 100 km =~60 miles, not 160 by your calc.

Howard Groopman

Good thing I like arithmetic. I knew it was 25K miles, and 1.6 kilos to a mile, so 40K.

Coral Harvey

I guessed 45 and was wrong. But seems I am not alone !

Player

michael Cogar, NASA says 40,000. Nat Geo is not always as reliable as it should be.

Louella Wilson

Marcella Kosse, easy! Multiply by 8/5 to convert miles to km. Gives a good everyday conversion. 5/8 for the reverse.

Jaimi McEntire

krkyates, Maybe 80? That would be my guess.

Jaimi McEntire

Lynne Zeman, Being from the states, you were taught the metric system in school for years.

Sean Philips

Ludlow Bushmat, But apparently it IS all about you and your need to whine about kilometres.

Eileen Dunn

Got it lucky guess

Mark L Thomas

Not 45?

Fred Keogh

If you want to roughly convert kilometres to miles, divide k's by 5 then multiply by 8.

Suraya Choudhury

I put 45 !

Lynne Zeman

Being from the States, I don't know the metric system and took a bad guess..... Ah, well. And Cheryl Perkins - being unwilling to adapt does not make us inferior - just different. Which is not necessarily a bad thing.