∴ Internal radius (r) = 3 cm Height of the tube (h) = 10 cm Thickness of the metal = 1 cm ∴ Outer radius (R) = Thickness of the metal +Internal radius = 1 + 3 = 4 cm ∴ Outer curved surface area =2πrh+πR2+π(R2−r2) =2π(3)(10)+π(4)2+π(16−9) =60π+16π+7π=83πsqcm