Question

3. 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
(1) inner curved surface area,
(ii) outer curved surface area,
(ii) total surface area.
Fig. 13.

plz give me answers frnds​

Answer 1

Answer:

inner curved surface area

According to the question inner diameter is 4 cm,

then,

Inner radius of a cylindrical pipe =r

1

=

2

innnerdiameter

=(

2

4

)cm=2cm

Height (h) of cylindrical pipe=77 cm,

Curved Surface Area of inner surface of pipe =2πr

1

h

=(2×

7

22

×2×77)cm

2

=968cm

2

(ii) Outer curved surface area

According to the question outer diameter is 4.4 cm

Outer radius of cylindrical pipe =r

2

=

2

outerdiamterer

=(

2

4.4

)cm=2.2cm

Height of cylinder = h = 77 cm,

Curved area of outer surface of pipe = 2πr

2

h

=(2×

7

22

×2.2×77)cm

2

=(2×22×2.2×11)cm

2

=1064.8cm

2