Question 896458
Look at the ends, first.  Each end is based on a circle, and the area of the inner circle is absent.
{{{OuterCircle-InnerCircle=EndArea}}} for 1 end.


Inner Diameter, 2.0 cm, radius 1.0 cm.
Outer Diameter, 2.4 cm, radius 1.2 cm.


The pipe has TWO of these ends.
{{{2(pi*1.2^2-pi*1.0^2)}}}
{{{2pi(1.2^2-1.0^2)}}}
{{{0.88pi}}}--------total of the ends.


Inner Surface:  {{{20*(2*1*pi)=40pi}}}
Outer Surface:  {{{20*(2*1.2*pi)=48pi}}}


ALL of surface area for this pipe:
{{{(0.88+40+48)(pi)}}} square centimeters.
{{{highlight(88.88(pi))}}} square centimeters.