#How do you find volume and surface area in Class 9? What is the name of Chapter 13 in maths class 9? What is total surface area Class 9? (iii)Total surface area = [Inner curved surface area] + [Outer curved surface area] + [Area of two circular ends] = [2πrh] + [2πRh] + 2[π(R2 – r2)] Area is the amount of surface a two-dimensional shape can cover, measured in square units. The SI unit of area is the square meter (m2), which is a derived unit.