A right circular cylinder just encloses a sphere of radius r. Find i)

1.	A right circular cylinder just encloses a sphere of radius r. Find i) surface area of the sphere ii) curved surface area of the cylinder iii) ratio of the areas obtained in (i) and (ii)
Answer» i) Radius of the sphere = radius of the cylinder = r ∴Surface area of the sphere = 4πr² ii) C.S.A. of cylinder = 2πr (2r) [∵ h = 2r] = 4πr² iii) Ratio of (i) and (ii) = 4πr² : 4πr² = 1:1

A right circular cylinder just encloses a sphere of radius r. Find i) surface area of the sphere ii) curved surface area of the cylinder iii) ratio of the areas obtained in (i) and (ii)

Answer»

i) Radius of the sphere = radius of the cylinder = r

∴Surface area of the sphere = 4πr²

ii) C.S.A. of cylinder = 2πr (2r) [∵ h = 2r]

= 4πr²

iii) Ratio of (i) and (ii) = 4πr² : 4πr² = 1:1