Actually Welcome to the Concept of the Surface Areas and Volumes.
Since, Volume of cone = 1/3 π r^2 h,
here, r = 10 Inches and h= 12 inches, also π =3.14
so, VOC = 1/3 π (10)^2 × (20)
VOC = 1/3(3.14)(100)(20)= 2093.33 inch^3
=> so the volume of the cone is 2093.33 cubic inches.