Question

a metal pipe is 77 cm long, the inner diameter of the cross- section is 4 cm and the outer diameter is 4.4cm. find the surface area of each end​

Answer 1

Answer:

Given,

Inner radius(r)=2cm

Outer diameter(D)=4.4cm

Length of metal pipe=77cm

If outer sphere diameter =4.4cm, then, it's radius=24.4

∴ Outer sphere radius(R)=2.2cm

Now, let us find inner curved surface area=?

As we know that,

Surface area of a sphere =2πrh sq.cm

where, π=722,r=2cm,h=77cm

∴ Inner curved surface area=2×722×2×77

=44×22 sq. cm

=968 sq. cm

∴ Inner curved surface area(s1)=968 sq.cm

Now, let us find outer curved surface area, as, we know that,

Surface area of outer sphere=2πRh sq. cm

where, π=722, R=2.2cm, h=77cm

so, we get,

Outer curved surface area=2×722×2.2×77cm2

=22×2×2.2×11cm2

=44×2.2×11cm2

=1064.8 sq.cm

∴ Outer curved surface area(s2)=1064.8 sq. cm

Now let us find total surface area as, we know that,

Total surface area = Inner surface area (s1)+Outer surface area