The surface area of the cylinder that forms the "sides" of the microvillus rod is given by the area of the curved surface of a cylinder with diameter (d) = 0.1 μm and height (h) =
1.0 μm.
The curved surface area of a cylinder is given by 2πrh, where r = d / 2 = 0.1 / 2 = 0.05 μm.
Thus, the curved surface area is given by

Therefore, the surface area of the cylinder that forms the "sides" of the microvillus rod is
