Question

In the example given below, the radius of the base of a cylinder and its height is given. Then find the curved surface area and total surface area.

r = 1.4 cm, h = 2.1 cm

Answer 1

Given: r = 1.4 cm and h = 2.1 cm

Curved surface area of cylinder and total surface area
Curved surface area of the cylinder = 2πrh

= `2 xx 22/7 xx 1.4 xx 2.1`

= `2 xx 22 xx 0.2 xx 2.1`

= 18.48 sq. cm

Total surface area of the cylinder = 2πr (h + r)

= `2 xx 22/7 xx 1.4(2.1 + 1.4)`

= `2 xx 22/7 xx 1.4 xx 3.5`

= `2 xx 22 xx 0.2 3.5`

= `30.80` sq. cm

∴ The curved surface area of the cylinder is 18.48 sq. cm and its total surface area is 30.80 sq. cm.