The volume of the cone is equal to 1/3 bh where b is the area of the base. since the base is a circle then b is equal to pi d^2/4. substituting to the formula, V = pi d^2/ 12 * h. pi is equal to 3.14. substituting the values given above, then V = 3.14* 9 cm^2/ 12 * 12 cm equal to 254.34 cm3.
