Question

Find the area of the sheet required to make a cylindrical container which is open at one side and whose diameter is 28 cm and height is 20 cm . find the approximate area of the sheet required to make a lid of height 2 cm for this container .

Answer 1

Dimensions of the cylindrical container:

diameter ( d ) = 28 cm

radius ( r ) = d/2 = 28/2 = 14 cm

Height ( H ) = 20 cm

Area of the sheet required to make the

container ( A ) = base area + L.S.A

= πr² + 2πrH

= πr( r + 2H )

= ( 22/7 ) × 14 [ 14 + 2 × 20 ]

= 22 × 2 × 54

= 2376 square centimetres

ii ) Dimensions of the lid :

radius( r ) = 14 cm

height ( h ) = 2 cm

Area of the sheet required to make the lid = πr( r + 2h )

= ( 22/7 ) × 14 [ 14 + 2 × 2 ]

= 22 × 2 × 18

= 792 cm²