20) D
Diameter of sphere = r x 2 = d
Height (or length) of cylinder = d
Radius of cylinder = r
Volume of cylinder = πr²h = πr²d
We need to find the fraction of space taken by the sphere
⁴⁄₃ πr³
πr²d
⁴⁄₃ r
d
Since d = 2r,
⁴⁄₃ r
2r
⁴⁄₃
2
⁴⁄₃ ÷ 2 = ⁴⁄₃ x ¹⁄₂ = ⁴⁄₆ = ²⁄₃