Question

find the surface area of a cylinder with height being 20.5 cm and radius 10cm
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Answer 1

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Hi ,

i ) Dimensions of the solid cylinder :

Height ( H ) = 10 cm

Diameter ( D ) = 7cm

Radius ( R ) = D/2 = 7/2 = 3.5 cm

Volume of cylinder ( V1) = πR²H

= ( 22/7 ) × ( 3.5 ) × ( 3.5 ) × 10

= 385 cm³ -----( 1 )

ii ) Dimensions of the cone :

height ( h ) = 4 cm

radius ( r ) = 3 cm

Volume of cone ( V2 ) = ( πr²h)/3

= ( 22 × 3 × 3 × 4 )/7

= 37.71 cm³ ------( 2 )

According to the problem given ,

Volume of Remaining solid

= V1 - 2 × V2

= 385 cm³ - 2 × 37.71 cm³

=385 - 75.43

= 309.57 cm³

Therefore ,

Volume of the remaining solid

= 309.57 cm³

I hope this helps you.

: )

Answer 2

Answer:

i ) Dimensions of the solid cylinder :

Height ( H ) = 10 cm

Diameter ( D ) = 7cm

Radius ( R ) = D/2 = 7/2 = 3.5 cm

Volume of cylinder ( V1) = πR²H

= ( 22/7 ) × ( 3.5 ) × ( 3.5 ) × 10

= 385 cm³ -----( 1 )

ii ) Dimensions of the cone :

height ( h ) = 4 cm

radius ( r ) = 3 cm

Volume of cone ( V2 ) = ( πr²h)/3

= ( 22 × 3 × 3 × 4 )/7

= 37.71 cm³ ------( 2 )

According to the problem given ,

Volume of Remaining solid

= V1 - 2 × V2

= 385 cm³ - 2 × 37.71 cm³

=385 - 75.43

= 309.57 cm³

Therefore ,

Volume of the remaining solid

= 309.57 cm³