Find the for an area of a sector with an arc length of 60 in and a radius of 15 inches

Arc length = radius * central angle (radians)
central angle (radians)= arc length / radius
central angle (radians)= 60 / 15
central angle (radians)= 4 radians

sector area =(central angle / 2) * radius^2
sector area = (4 / 2) * 225
sector area = 450

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

Where’s the following prism