A cylindric

Let the radius of the base of conical ice cream = x cm

Then, height of the conical ice cream = 2 × diameter

= 2 × (2x)

= 4x cm

Volume of ice- cream cone

= Volume of conical portion + Volume of hemispherical portion

= 2πx³ cm³

Now,

Diameter of cylindrical container = 12cm

So, radius = 6cm

and height = 15cm

∴ Volume of cylindrical container = πr²h

= π × (6)² × (15)

= 540π cm³

⇒ x³ = 27

⇒ x = 3

So, the radius of the base of conical ice cream is 3cm

Hence, the diameter of the base of conical ice-cream = 2×3 = 6cm