Question

an iron pipe 20 cm long has external diameter equal to 20 CM if the thickness of the pipe is 1 m find the whole surface of the pipe

Answer 1

Though your question is incorrect. I think the thickness must be equal to 1 cm.

External radius(R)=10 cm

Internal radius(r)=10-1=9cm

length of pipe = 20 cm

Whole surface are = 2*pi*r*h + 2*pi*R*h+2*pi*(R^2-r^2)

=2*pi(r*h + R*h +(R-r)(R+r)

2×22/7(180+200+19)

2*22/7*(409)

=17996/7

=2570.85 cm^2

Answer 2

i got this answer.....