Maths problem.
30 August 2014, 11:34 AM
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Maths problem.
Two circles have radii differing by 1mm.
The area of the space between them is 32mm sq.
What are the radii of the two circles?
30 August 2014, 11:37 AM
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Just as you were nodding off...
30 August 2014, 11:48 AM
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30 August 2014, 11:50 AM
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30 August 2014, 11:53 AM
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Too slow
30 August 2014, 12:48 PM
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Quote:
Originally Posted by
f1_fan
Too slow
Was the crappy iphone calculator
30 August 2014, 02:23 PM
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Would it not be 1.7 and 2.7
30 August 2014, 03:01 PM
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No it's 4.6 and 5.6.
We had done it by the time I've just looked now.
If you put those two values into (pi x R^2)- (pi x r^2) you get 32.
Thanks to all who responded.
Clue: the way to do it isn't to use R and r for the two radii, but to use r and (r+1).
Then you only have one unknown.
30 August 2014, 03:08 PM
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Yes you should get r = 16/pi - 1/2
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