Convert units before differentiating a conical pile

Sand from a chute forms a conical pile whose altitude is always $4/3$ of its base radius.

(i) How fast is its volume increasing when the radius is $1$ m and increases at $1/8\text{ cm s}^{-1}$?4 marks

(ii) How fast is its radius increasing when it is $2$ m and the volume increases at $1000\text{ cm}^3\text{ s}^{-1}$?3 marks