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प्रश्न
The ratio between the curved surface area and the total surface area of a right circular cylinder is 1 : 2. Find the ratio between the height and radius of the cylinder.
उत्तर
Curved surface area of a cylinder = 2πrh
Total surface area of a cylinder = 2πr(r + h)
The ratio between the curved surface area and the total surface area of a cylinder is 1 : 2.
∴ `1/2 = (2pirh)/(2pir(r + h))`
⇒ `1/2 = h/((r + h))`
⇒ 2h = (r + h)
⇒ 2h – h = r
⇒ h = r
∴ Ratio of height and radius = 1 : 1.
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