Question 218148
r= 2*sqrt(5L)
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for  r=50
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50 =2*sqrt(5L)
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25= sqrt(5L),,,,square  both  sides
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625 = 5L
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125  ft = L
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check,,,r= 2*sqrt(5*125) = 2*sqrt625 = 2*25 =50,,,,,ok
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