Question

A metal pipe is 77 cm. long. The inner diameter of a cross section is 4 cm.,
the outer diameter being 4.4 cm. (see figure) Find its
(i) inner curved surface area
m) outer curved surface area
() Total surface area​

Answer 1

Answer :

Height : 77cm

Inner diameter : 4cm

Inner radius : 4cm/2 : 2cm

Outer diameter : 4.4cm

Outer diameter : 4.4cm/2 : 2.2cm

INNER CURVED SURFACE AREA

Inner radius : 2cm

Height : 77cm

curved surface area

2πrh

2 x 22/7 x 2cm x 77cm

2 x 22 x 2cm x 11cm

4 x 22cm x 11cm

88cm x 11cm

968cm²

OUTER CURVED SURFACE AREA

Height : 77cm

Outer radius : 2.2cm

Curved surface area

2πrh

2 x 22/7 x 2.2cm x 77cm

2 x 22 x 2.2cm x 11cm

22 cm x 48.4 cm

1064.8cm²