The difference between the outer and inner curved surface areas of a hollow right circular cylinder 14 cm long is 88 cm2. If the volume of metal used in making the cylinder is 176 cm3, find the outer and inner diameters of the cylinder.
Height of hollow cylinder =14 cm
Let the radius of outer radius be ‘R’ cm
Let the radius of inner radius be ‘r’ cm
Difference between inner and outer Curved surface area= 88 cm
Curved surface area of hollow cylinder
⇒ 2π(R – r)h = 88
⇒ R – r = 1 ……… (1)
Volume of metal = 176
Height of hollow cylinder = 14 cm
Volume of hollow cylinder (metal) =
⇒ (R + r)(R – r) = 4
⇒ (R + r) = 4 ………… (2)
Solving (1) and (2) we get,
R = 2.5cm
r = 1.5cm
∴ Outer diameter cm
= 5 cm
Inner diameter cm
= 3 cm