Question

The interior of a building is in the form of cylinder of diameter 10m and height 8m, surmounted by a cone whose vertical angle is a right angle.

Then what will be the area of the surface and the volume of the building?​

Answer 1

Hope it helps.

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Answer 2

• Surface Area = 399.4 m²
• Volume = 1675.5 m³

Explanation:

Lateral Surface Area of the Cylindrical Part

• 2πrh
• 2 x π x 5 x 8
• 80 x π
• 251.3 m²

Slant height of cone

• √r² + h²
• √25 + 64
• √89
• 9.43 m

Surface Area of Conical Portion

• πrl
• π x 5 x 9.43
• 47.15 x π
• 148.1 m²

Total Surface Area :

• 251.3 + 148.1
• 399.4 m²

Volume

• V = πr²h + 1/3πr²h
• V = πr²h (1 + 1/3)
• V = π x 25 x 8 x (4/3)
• V = π x 1600/3
• V = 1675.5 m³