Question 719533
Exactly how is the shading distributed?  


For the arc length of the the 78 degrees, since the radius is 6 (for the circle), the circumference would be {{{2*pi*6=12*pi}}}.  The proportion of the circumference equaling the arc length is {{{78/360}}}, so this means that the arc length for the 78 degrees portion is {{{(78/360)*12*pi}}}.  More simplified, be 78*pi/30=39*pi/15={{{highlight(13*pi/5)}}}.