Question

A metal pipe is 77cm long, the inner diameter of the cross section is 4 cm and the outer diameter is 4.8 cm. find the inner curved surface area , outer curved surface area and total surface area.

Answer 1

h = 77 cm , inner diameter = 4 cm
Outer diameter = 4.8 cm
Inner radius = 2 cm , outer radius = 2.4 cm .

Inner curve surface area = curve surface area

Inner Curve surface area = 2x 22/7x r x h
= 2 x 22/7 x 2 x 77
= 968 sq.cm

Outer curve surface area = 2x 22/7 x r x h
= 2 x 22/7x 2.4 x 77
= 1161.6 sq.cm

Total surface area = outer curve surface area + inner curve surface area .
= 1161.6 + 968 = 2129.6 sq.cm

Answer 2

Answer:

(1) 968cm^2 , (2) 1161.6cm^2 , (3) 2150.12

Step-by-step explanation:

(1) Inner curved surface area = 2*π*r*h

Inner diameter = 4cm

Radius = 4/2 = 2cm

=2*22/7*2cm*77

=968cm^2

(2) Outer curved surface area = 2πrh

Outer diameter = 4.8cm

Radius = 4.8/2 = 2.4cm

= 2*22/7*2.4cm*77cm

=1161.6cm^2

(3) the cross section of the area is present at two ends of the cylinder.

TSA of cylinder = Inner curved surface area + Outer curved surface area+2*cross section surface area

TSA of cylinder =

968cm^2 + 1161.6cm^2 * 2π( r^2 - r )

968cm^2 + 1161.6cm^2 + 2*22/7 (2.4cm*2.4cm - 2.4cm)

= 2129cm + 2 *22/7*3.36cm^2

= 2129 + 147.84/7

= 2150.12cm^2