<PRE><B>Question 968360</B>
A central angle of 140º subtends an arc of length 10 feet on a circle. Find the radius of the circle 
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140 degrees = 140(pi/180) = (7/9)pi radians
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Equation:
theta in radians = (arc length)/(radius)
(7/9)pi = 10/radius
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radius = 10/[(7/9)pi] = 90/(7pi) is approximately 4.09 ft
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Another way to work it using proportions::

circum/360 = arc/central angle
cir/360 = 10/140
cir = 3600/140 = 25.71
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2*pi*r = 25.71
radius = 25.71/(2*pi) = 4.09 ft.
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Cheers,
Stan H.
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