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End of Year Geography Quiz, Question 16:

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  • 26mi235
    replied
    Re: End of Year Geography Quiz, Question 16:

    Originally posted by gh
    16. Approximately how big is the world?

    a. 97 million square miles

    b. 197 million square miles

    c. 297 million square miles

    d. 397 million square miles

    e. really-really big

    (OK, I'm just screwing with you; e isn't one of the choices)
    Since I have virtually absent, I will take a crack without looking below; knowing this as a 'fact' is silly, but knowing that the earth is almost a sphere and that the kilometer was defined on the basis of the size of the earth -- pole to equator, I think, an educated mind gets the following (if silly mistakes are avoided.

    surface area = 4 pi r^2 (four of my buildings - I work in the Pyare Square building). The circumference of the earth is ~40,000km = 2 pi r, so r ~ 20,000/pi . Thus 4 pi r^2 is ~4 x pi x (2x10^4/pi)^2 = 4x4x10^8/pi ~ 5x10^8 or 500,000,000+km^2. Since 1km ~ 0.62mi, 1km^2 is ~ 0.384sq mi, or

    192,000,000+ sq mi

    Since both 500,000,000 is under by under by about 2% and the French measured the equator to pole, so the circumference of the not-quite-spherical earth is a bit larger, this is pretty close to "b", 197 million.

    [I hope that I did not screw this up; now I will look at the answers]

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  • bambam
    replied
    Steven Wright once noted, "Its a small world - but I wouldn't want to have to paint it."

    Leave a comment:


  • Marlow
    replied
    Where's the metriphiles denouncing the question as altogether ridiculous ??!! :wink:

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  • DrJay
    replied
    After I answered, I looked it up and indeed the formula is 4pi(r)2 (I don't know how to do pi and squares and whatnot on my keyboard). And I believe that would be the derivative of 4/3pi(r)3, which fits (calculus was long ago).

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  • gh
    replied
    Originally posted by DrJay
    I'm going with b, 197 million. The volume of a sphere is 4/3¶r3 but I can't remember the exact formula for the surface area, but 4pi(radius)2 seems about right, which gives 201 million if you use 4000 miles for the radius.
    whatever the rationale, you got it right!

    Leave a comment:


  • mcgato
    replied
    Originally posted by wineturtle
    3000 miles from Maine to Flalala????
    After Dr Jay posted, I thought that 3000 was too much. If I did 2500 instead, I would get an answer around 187 million. Kind of funny too, since I took the 4 minute quiz that you linked and correctly got the distance from NYC to LA as 2500 miles.

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  • wineturtle
    replied
    Originally posted by mcgato
    I'll go for c.

    Reasoning as follows:
    US is about 3000 by 3000 miles.
    US is about 10% of the world land mass.
    Land mass is about 1/3 of the earth.

    Multiply out to 270 million square miles. Close to c.

    3000 miles from Maine to Flalala????

    Leave a comment:


  • wineturtle
    replied
    Agree w/Dr Jay `60 million land and 130 million water covered miles is stuck somewhere in my mind.

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  • rasb
    replied
    It has to be (e). This looks like the old double reverse play to me.

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  • DrJay
    replied
    I'm going with b, 197 million. The volume of a sphere is 4/3¶r3 but I can't remember the exact formula for the surface area, but 4pi(radius)2 seems about right, which gives 201 million if you use 4000 miles for the radius.

    Leave a comment:


  • mcgato
    replied
    I'll go for c.

    Reasoning as follows:
    US is about 3000 by 3000 miles.
    US is about 10% of the world land mass.
    Land mass is about 1/3 of the earth.

    Multiply out to 270 million square miles. Close to c.

    Leave a comment:


  • gh
    started a topic End of Year Geography Quiz, Question 16:

    End of Year Geography Quiz, Question 16:

    16. Approximately how big is the world?

    a. 97 million square miles

    b. 197 million square miles

    c. 297 million square miles

    d. 397 million square miles

    e. really-really big

    (OK, I'm just screwing with you; e isn't one of the choices)
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