If i'm not mistaking, finding the area of a sector should be x/area of the circle = sector measurement/360 and for example the shaded sector measurement is 60 degrees and the area is 250cm^2 your formula will look like this x/250=60/360 then you cross multiply.
Arc length formula = n degrees/360 degrees x 2 TT r (TT is pi)
Central angle formula = arc length * 180 degrees/pi * r
