Given: Diameter of each solid sphere = 6 cm

∴ Radius of each sphere = 6/2 = r_s = 3 cm

Diameter of cylinder = 4 cm

∴ Radius of cylinder = 4/2 = r_c = 2 cm

Height of cylinder = h = 45 cm

Formula: volume of sphere = (4/3) × π × r_s³

Volume of cylinder = π × r_c² × h

Spheres are moulded to form cylinder which means the volume remains the same

Let ‘n’ be the number of spheres required

i.e. volume of n spheres = volume of cylinder

∴ n × (4/3) × π × 3³ = π × 2² × 45

n × 4 × 27 = 4 × 3 × 45

n = 45/9 = 5

Number of solid spheres made = 5