A 20 m long iron pipe has an exterior diameter of 25 cm. If the thickness of the pipe is 1 cm, find the internal curved surface area of the pipe
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The diameter of the base = 25cm hence the radius is R=12.5cm
The radius of the circle base is r = R – thickness = 12.5–1=11.5cm
The height is h=20cm
The whole Surface Area of the pipe =2πRh+2πrh+2π(R^2−r^2)
=2⋅3.14⋅12.5⋅20+2⋅3.14⋅11.5⋅20+2⋅3.14(12.52−11.52)
=1570+1444.44+6.28(156.25–132.25)
=3014.4+148.8
=3163.2 sq.cm
The radius of the circle base is r = R – thickness = 12.5–1=11.5cm
The height is h=20cm
The whole Surface Area of the pipe =2πRh+2πrh+2π(R^2−r^2)
=2⋅3.14⋅12.5⋅20+2⋅3.14⋅11.5⋅20+2⋅3.14(12.52−11.52)
=1570+1444.44+6.28(156.25–132.25)
=3014.4+148.8
=3163.2 sq.cm
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