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The outer diameter of a spherical shell is 12 cm and it`s inner diameter is 8 cm . Find the volume of themetal used and it`s outer surface area . |
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Answer» Answer: Volume of the metal used = 636.95 cm³ Outer surface AREA of the SPHERICAL shell = 452.57 cm² Step-by-step explanation: Given :
To find : the volume of the metal used and it's outer surface area. Solution : Radius is half the diameter. ⟼ Outer radius of the spherical shell = 12/2 = 6 cm ⟼ Inner radius of the spherical shell = 8/2 = 4 cm Volume of the sphere = 4/3 × πr³ where r denotes radius of the sphere. Volume of the outer shell = 4/3 × 22/7 × 6³ = 4/3 × 22/7 × 216 ≈ 905.15 cm³ Volume of the inner shell = 4/3 × 22/7 × 4³ = 4/3 × 22/7 × 64 ≈ 268.20 cm³ Volume of the metal used = Volume of the outer shell – volume of inner shell = 905.15 – 268.20 = 636.95 cm³ Outer surface area : Outer radius of the spherical shell = 6 cm Outer surface area = 4πr² = 4 × 22/7 × 6² = 88/7 × 36 = 452.57 cm² |
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