Area = (angle/2π)*π*r^2 because the area of a sector is basically the total area (π*r^2) divided by the fraction of the whole (angle/2π). 2π = the whole of the circle in radians.
So for your problem Area = (5π/2/2π)*π*(4^2) = (5π/4π)*π*(16) = (5/4)*(3.14)*(16) = 20*(3.14) = 62.8
Hope this helps!
