Question 1094939
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Use the formula 


S = {{{r*alpha}}}   (1)


for the arc length S, where "r" is the circle radius and {{{alpha}}} is the central angle in radians.


To use it, you need first to convert 128 degs 18 minutes to radians.


128 degs 18 minutes = 128*60 + 18 minutes = 7698 minutes.


{{{2pi}}} radians = 360 degs = 360*60 = 21600 minutes.


So, 128 degs and 18 nimutes = {{{(2pi)*(7698/21600)}}} = 2.2381 radians.


So, your equation (1) now becomes

36.90 = 2.2381*r.


From it,  calculate r = {{{36.90/2.2381}}}.


Then double your "r" to get he diameter.
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