The difference between the outside and inside surface of a cylindrical metallic pipe 14cm long is 44 cm squared.if the pipe is made of 99 cm cube of metal find the outer and inner radii of the pipe. Explain pls
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Let the outer and inner radii be R and r
height=14cm
outer c.s.a=2×pi×R×h
=2×22/7×R×14
=(88R)cm^2
inner c.s.a=2×22/7×r×14
=(88r)cm^2
now,(88R-88r)=44
88(R-r)=44
R-r=1/2 (i)
External volume=pi×R^2×h
=22/7×R^2×14
=(44R^2)cm^3
internal volume=pi×r^2×h
=22/7×r^2×14
=(44r^2)cm^3
now,44R^2-44r^2=99
44(R^2-r^2)=99
R^2-r^2=9/4 (ii)
on dividing eq.(ii) from (i)
we get (R+r)=9/2 (iii)
on solving eq.(i) &(iii)
we get:R=5/2 &r=2
so,outer R=2.5cm
inner r=2cm
height=14cm
outer c.s.a=2×pi×R×h
=2×22/7×R×14
=(88R)cm^2
inner c.s.a=2×22/7×r×14
=(88r)cm^2
now,(88R-88r)=44
88(R-r)=44
R-r=1/2 (i)
External volume=pi×R^2×h
=22/7×R^2×14
=(44R^2)cm^3
internal volume=pi×r^2×h
=22/7×r^2×14
=(44r^2)cm^3
now,44R^2-44r^2=99
44(R^2-r^2)=99
R^2-r^2=9/4 (ii)
on dividing eq.(ii) from (i)
we get (R+r)=9/2 (iii)
on solving eq.(i) &(iii)
we get:R=5/2 &r=2
so,outer R=2.5cm
inner r=2cm
shyamsneha:
Thank u Soo much!
mention not
if you like it mark it as brainliest answer
It is the only answer so obviously it is brainliest
thanks
I did the same thing.Only instead of dividing by 2 I multipled
take care of these small mistakes because a simple mistake can prove your answer wrong
have you mark my answer brainliest
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I also don't know because I am a new user but you can ask it from your friends
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