Question

The radii of the ends of a bucket 16 cm height are 20 cm and 8 cm. The curved surface area of the bucket is

विकल्प

• 1760 cm²

•  2240 cm²

•  880 cm²

•  3120 cm²

Answer 1

Radius of top of bucket r₁ = 20 cm

Radius of bottom of bucket r₂ = 8 cm

Height of bucket = 16 cm

The curved surface area of bucket  `= pi (r_1 +r_2) l`

`l = sqrt(h^2 + (r_1 +r_2)^2)`

`= sqrt(16^2 + (20 - 8)^2)`

`=sqrt(256 + 144)`

`l = sqrt400`

`l = 20 "cm"`

C.S.A. of bucket

` = pi (20 + 8) xx 20`

`= 22/7 xx 28 xx 20`

`=22 xx 80`

= \[1760 \ cm^2\]