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 Fig. 13.11). Find its
(i) inner curved surface area,
(ii) outer curved surface area,
(iii) total surface area
which book

Answer 1

Step-by-step explanation:

ANSWER

Given:

⇒Inner radius =

2

4

=2 cm =r

1

⇒Outer radius =

2

4.4

=2.2cm =r

2

⇒Height =77 cm

Solution:

(i) Curved S.A=2πr

1

h (inner)

=2×

7

22

×2×77=968 cm

2

(ii) Curved S.A (outer)=2πr

2

h

=2×

7

22

×2.2×77cm

2

=(22×22×2.2) cm

2

=1064.8cm

2

(iii) Total S.A of pipe = CSA of inner surface + CSA of outer surface + Area of circural base and top

=968+1064.8+2π((2.2)

2

−2π(2)

2

)

=2032.8+5.28 cm

2

=2038.08 cm

2