Question

5. 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
(1) inner curved surface area
(i) outer curved surface area
(i) Total surface area.​

Answer 1

Answer:

HOPE IT HELPS U !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I TRIED MY BEST !!!!!!!!!!!!!!!!!

PLS MARK ME AS BRAINLIEST FOR MY HARDWORK !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Step-by-step explanation:

(i) inner curved surface

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

(iii) Total surface area

Total surface area = curved surface area of inner cylinder + curved surface of outer cylinder + 2 × Area of base

Area of base = area of circle with radius 2.2 cm - Area of circle with radius 2 cm

=πr  2 2 −πr  12

=  7 22 ×((2.2)  2

−(2.)  2 )

=  7 22 ×(4.84−4)

=  7 22×(0.84)

=2.74cm  2

Total surface area = curved surface area of inner cylinder + curved surface area of outer cylinder + 2 × Area of base

=968+1064.8+2×2.74

= 2032.8 + 5.76

=2039.08cm  2

Therefore, the total surface area of the cylindrical pipe is  

=2039.08cm  2