Question

a metal pipe is 77 cm long the inner diameter of the cross section is 4 cm and the outer diameter is 4.8 cm find its inner curved surface area, outer curved surface area and total surface area

Answer 1

r=2cm
R=2.4cm
Inner CSA=$2 * \pi *r*h$
               = 2*22/7*2*77
               =968cm^2
Outer CSA=$2* \pi *R*h$
                =2*22/7*2.4*77
                 =1161.6cm^2
TSA=inner CSA+outer CSA+two base area
two base area=[tex]2( \pi R^2- \pi r^2) =2 \pi (R^2-r^2)[/tex]
                       = 2*22/7((2.2)^2-(20^2)
                        =2*22/7*4.2*0.2
                         =5.28cm^2
TSA =968+1161.6+5.28
        =2134.88cm^2