So we want to know how much clay did Joseph add after he built the cone. So the formula for the volume of the cone is V=(1/3)*pi*r^2*h where r is the radius and h is height. We know h1=12cm and r1=6cm, r2=6cm and h2=18 cm. So to get the amount of added clay Va we simply subtract the volume of the clay of the first cone V1 from the volume of the second cone V2: Vd=V2-V1=(1/3)*pi*(r1^2)*h1 - (1/3)+pi*(r2^2)*h2. Va=678.24 cm^3-452.39 cm^3= 266.08 cm^3.
