A iron pipe 20cm long has exterior diameter equal to 25cm.if the thickness of the pipe is 1cm,find the whole surface of the pipe.
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Height=20 cm
External diameter=25 cm
Internal diameter=(25 - 1)=24 cm
E. radius=12.5 cm
I. radius=12 cm
T.S.A.= external c.s.a. +internal c.s.a.+2(π(R-r))
=2πRh +2πrh +2(π(R-r))
=2×22/7×12.5×20+2×22/7×12×20+2(22/7(12.5-12)
=11,000/7+10,560/7+22/7
=21,582/7 cm2
External diameter=25 cm
Internal diameter=(25 - 1)=24 cm
E. radius=12.5 cm
I. radius=12 cm
T.S.A.= external c.s.a. +internal c.s.a.+2(π(R-r))
=2πRh +2πrh +2(π(R-r))
=2×22/7×12.5×20+2×22/7×12×20+2(22/7(12.5-12)
=11,000/7+10,560/7+22/7
=21,582/7 cm2
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