Question
A solid metallic rectangular block of dimensions 112 cm
× 44 cm × 25 cm is melted and recast into a cylinder of radius 35 cm. The curved surface area (in cm²) of the cylinder is: (Take π  = 22/7)Solution
Let the height of the cylinder be h According to the question, 112 × 44 × 25 = (22/7) × 352 × h ⇒ (112 × 44 × 25 × 7)/(22 × 35 × 35) = h ⇒ h = 32 So, the height of the cylinder = 32 cm Now, Curved surface area of the cylinder = 2 × (22/7) × 35 × 32 ⇒ 44 × 5 × 32 ⇒ 7040 ∴ The curved surface area (in cm2) of the cylinder is 7040.
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