Solution:-
1. Radius (r) of the sphere = 10 units. (Given)
• Surface area of the sphere = 4πr².
Surface area of the sphere = 4 × π × (10)²
Surface area of the sphere = 4 × π × 10 × 10
Surface area of the sphere = 400π units. (Ans)
And,
• Volume of the sphere = 4/3πr³.
Volume of the sphere = 4/3 × π × (10)³
Volume of the sphere = 4/3 × π × 10 × 10 × 10
Volume of the sphere = 4000π/3
Volume of the sphere = 1333.3π cubic units. [approx] (Ans)
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2. Diameter of the sphere = 16 units. (Given)
Radius (r) of the sphere = 16/2 = 8 units.
• Surface area of the sphere = 4πr².
Surface area of the sphere = 4 × π × (8)²
Surface area of the sphere = 4 × π × 8 × 8
Surface area of the sphere = 256π units. (Ans)
And,
• Volume of the sphere = 4/3πr³.
Volume of the sphere = 4/3 × π × (8)³
Volume of the sphere = 4/3 × π × 8 × 8 × 8
Volume of the sphere = 2048π/3
Volume of the sphere = 682.6π cubic units. [approx] (Ans)
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3. Radius (r) of the sphere = 5 units. (Given)
• Surface area of the sphere = 4πr².
Surface area of the sphere = 4 × π × (5)²
Surface area of the sphere = 4 × π × 5 × 5
Surface area of the sphere = 100π units. (Ans)
And,
• Volume of the sphere = 4/3πr³.
Volume of the sphere = 4/3 × π × (5)³
Volume of the sphere = 4/3 × π × 5 × 5 × 5
Volume of the sphere = 500π/3
Volume of the sphere = 166.6π cubic units. [approx] (Ans)
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4. Diameter of the sphere = 18 units. (Given)
Radius (r) of the sphere = 18/2 = 9 units.
• Surface area of the sphere = 4πr².
Surface area of the sphere = 4 × π × (9)²
Surface area of the sphere = 4 × π × 9 × 9
Surface area of the sphere = 324π units. (Ans)
And,
• Volume of the sphere = 4/3πr³.
Volume of the sphere = 4/3 × π × (9)³
Volume of the sphere = 4/3 × π × 9 × 9 × 9
Volume of the sphere = 2916π/3
Volume of the sphere = 972π cubic units. (Ans)
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