I would like to know how to transpose the following equation to make x the subject given that it is based on the formula for arc length - Arc Length = angle size/360 x 2 pi r

The equation is expressed with all given information:

15 = 40/360 x 2 pi x

15 = 40/360 x 2 pi x

15 = 1/9 * 44/7 x

15 = 44/63 x

x = (15) / (44/63)

x = 945/44

x = 21.47727