Solution:

(i)Given radius, r = 6 cm

Height, h = 7 cm

Volume of the cone = (1/3)r²h

=(1/3)×(22/7)×6²×7

= 22×12

= 264 cm³

Hence the volume of the cone is 264 cm³.

(ii) Given radius, r = 3.5 cm

Height, h = 12 cm

Volume of the cone = (1/3)r²h

=(1/3)×(22/7)×3.5²×12

= (22/7)×12.25×4

= 154 cm³

Hence the volume of the cone is 154 cm³.