In a circle of radius 10 cm, a sector has an area of 40 sq. cm. what is the degree measure of the arc of the sector?

Sector area = (central angle / 360) * PI * radius^2
40 = (central angle / 360) * PI * 10^2
40 = (central angle / 360) * 314.159265
central angle = 360* 40 / 314.159265
central angle = 14,400 / 314.159265
central angle = 45.8366236628 degrees

Source:
http://www.1728.org/radians.htm