Area of a sector (A) with a central angle (€) of 5π/7 radians and a diameter of 5.6 in. Use 3.14 for π, radius (r) = d/2 = 5.6/2 = 2.8in. A = (€ radians/2π radians)•π r^2 A = (5π7 radians/2π radians)•π (2.8in)^2 A = 5/14•π 7.84 in^2 A = 0.357•3.14•7.84 in^2 A = 8.79 in^2