Answer:
40π/3 cm^2
Step-by-step explanation:
The centerline of the shaded region has a radius of 3 +4/2 = 5 cm. Its length is 1/3 of a circle with that radius, so is ...
length of centerline = (1/3)(2π·5 cm) = (10/3)π cm
The shaded region is 4 cm wide, so the area is the product of that width and the centerline length:
(4 cm)(10/3 π cm) = 40π/3 cm^2
