Question

225) A hemispherical tank is made of steel 21cm thick. The inner radius of the tank is 35cm.
Find the volume of steel used in making the tank. (rt =)
22​

Answer 1

The inner radius of the tank is 35 cm.

So, the inner radius of the hemispherical tank (r1) = 35 cm

Also, the hemispherical tank is made of steel 21 cm thick.

So, r2 = inner radius + outer radius = (35 + 21) cm = 56 cm

Now,

The volume of iron used = Volume of outer radius - Volume of inner radius

⇒ 2/3 π (r2)³ - 2/3 π (r1)³

⇒ 2/3 × 22/7 [(56)³ - (35)³]

⇒ 44/21 (175616 - 42875)

⇒ 44/21 (132741)

⇒ 44(6321)

⇒ 278124 cm³

To convert cm³ into m³ divide the value by 10^6

⇒ 0.27812 m³

Answer 2

Given :-

• Inner Radius = 35cm.
• Thickness of Stell = 21cm.

To Find :-

• Volume of Steel used in making The tank ?

Formula used :-

• Volume of Steel used = Outer Volume - Inner Volume = [(2/3) π * R³ ] - [(2/3) π * r³ ]

Solution :-

Given That,

→ Inner Radius = 35cm. = r

→ Outer Radius = inner Radius + Thickness = 35 + 21 = 56cm = R.

Putting Both Values we get :-

→ Volume = [(2/3) π * R³ ] - [(2/3) π * r³ ]

→ V = [(2/3) π * 56³ ] - [(2/3) π * 35³ ]

Taking (2/3) * π common,

→ V = (2/3) * π [ 56³ - 35³ ]

→ V = (2/3) * π [ 175616 - 42875 ]

→ V = (2/3) * (22/7) * 132741

→ V = (44 * 132741) / 21

→ V = 278124 cm³

Hence, Volume if Steel used in Making The tank is 278124cm³.