A solid sphere of radius 3 cm is melted to form a hollow cylinder of height 4 cm and external diameter 10 cm. What is the thickness of the cylinder?

Given:

A solid sphere of radius 3 cm is melted to form a hollow cylinder of height 4cm & external diameter 10cm.

Formula used:

Volume of sphere = 4/3π r³

Volume of hollow cylinder = π(R² - r²)h

Thickness of cylinder = External radius - Internal radius

Calculation:

According to the question,

External diameter = 10cm

External radius = 10/2= 5cm

Volume of sphere = Volume of hollow cylinder

⇒ 4/3π (3³) = π(5²-r²)4

⇒ 9 = 25 - r²

⇒ r² = 16

⇒ r = 4

Thickness of cylinder = 5 - 4 = 1 cm

∴ The thickness of the cylinder is 1 cm.