median
don steward
mathematics teaching 10 ~ 16

Thursday, 26 March 2009

space per person

the world's population is presently around 7 billion
[the website http://www.worldometers.info/ shows updated data as a digital display]

the average diameter of the Earth (giant blue marble) is 12,742,000 m.

water makes up 71% of the Earth's surface




how much space is this per person?

[area of a sphere = 4 x pi x r^2]

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