Question 815577
a = pi * r^2
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inner ring difference area (d):
d = pi * 8.4^2 - pi * 6.3^2
d = pi * 8.4^2 - pi * 6.3^2
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Answer 1:
d = 96.98 sq.cm
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outer ring difference area (d):
d = 96.98 sq.cm = pi * r^2 - pi * 8.4^2
96.98 = pi * r^2 - pi * 8.4^2
96.98 = pi * r^2 - pi * 70.56
96.98 = pi * ( r^2 - 70.56 )
96.98/pi = r^2 - 70.56
96.98/pi + 70.56 = r^2
r^2 = 101.43
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Answer 2:
r = 10.07 cm
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