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One for the math minds
http://byap.backyardmagazines.com/forum/viewtopic.php?f=5&t=8823
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Author:  earthbound [ Jan 5th, '11, 22:24 ]
Post subject:  One for the math minds

Ok this is just a quick one because I'm failing to remember my high school maths and I'm hoping someone out there can help..

I'm trying to work out how to represent a cubic kilometre volume as a sphere, this is all sort of related to this thread and something I'm trying to work out and graphically represent.

I know the volume is 16308.5 km3

i know the formula for spheres is 4/3*Pi*radius3

so now how to I work out the radius of the sphere "x"?

Do we put both sides over one and start swapping some numbers around? I'm struggling but I remember this sort of thing can be worked out. I never was much good at algebra..

Author:  SolTun [ Jan 5th, '11, 23:48 ]
Post subject:  Re: One for the math minds

http://www.calculatorsoup.com/calculato ... sphere.php

Author:  SolTun [ Jan 5th, '11, 23:54 ]
Post subject:  Re: One for the math minds

r = 157.31681 m
V = 16308500 m3
A = 310999.81223 m2
C = 988.45067 m

Author:  orcy2010 [ Jan 6th, '11, 05:06 ]
Post subject:  Re: One for the math minds

Just rearrange for the values of interest

V=4/3 * pi * R^3

3V/4pi = R^3

CubeRoot(3V/4pi) = R

I think. Dont have time to work it out with the numbers you gave. Otherwise, use the calculator Sol posted



cheers

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