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 the
1. inner curved surface area
2. outer curved surface area
3. total surface area

Answer 1

Solution:
1.inner curved surface area(a)=2πrh+2πr2
                                            =2·π·4·77+2·π·42
                                            =2035.75
2.outer curved surface area(b)=2πrh+2πr2
                                            =2·π·4.8·77+2·π·4.82
                                            =2467.03
3.total surface area= a + b
                               =2035.75+2467.03
                               =4502.78