Question

An iron pipe 20 cm long has external radius equal to 12.5 nd internal radius of 11.5 find tsa

Answer 1

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Given ,length of pipe ( h ) = 20 cm

let external radius ( R) = 12.5 cm

internal radius ( r ) = 11.5 cm
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Find total surface area of the pipe(TSA):
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=2 π h ( R + r ) + 2 π ( R^2 - r^2 )

=2 π [ h ( R + r ) + ( R^2 - r^2 ) ]

=2 π [ 20( 12.5 + 11.5 ) + { (12.5)^2 - ( 11.5 )^2 } ]

=2 π ( 20 × 24 + 24 )

=2 π { 24 ( 20 + 1 ) }

=2 π × 24 × 21

=2 × 22 × 24 × 21 / 7

=3168 cm^2

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Your Answer : TSA = 3168 cm^2
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