HomeClass: 9 Surface Area of a Right Circular Cylinder | Class: 9 | Chapter: 13 | Exercise: 13.2 Surface Area of a Right Circular Cylinder If we fold a rectangular sheet with one side as its axis then it forms a cylinder. It is the curved surface of the cylinder. And if this curved surface is covered by two parallel circular bases then it forms a right circular cylinder. Right Circular Cylinder – with radius and height Curved Surface area = Total surface area = Surface Area of a Hollow Right Circular Cylinder If a right circular cylinder is hollow from inside then it has different curved surface and volume. Hollow Cylinder Each base surface area = Curved surface area = Total surface area = Example Find the Total surface area of a hollow cylinder whose length is 22 cm and the external radius is 7 cm with 1 cm thickness. (π = 22/7) Solution Given, h = 22 cm R = 7 cm r = 6 cm (thickness of the wall is 1 cm) Total surface area of a hollow cylinder = 2πh(R + r) + 2π(R2 - r2) = 2(π) (22) (7+6) + 2(π)(72 - 62) = 572 π + 26 π = 598 π = 1878.67 cm2 Tags: Class: 9 Facebook Twitter
