Explanation:
the volume of a cone (as for pyramids) is
base area × height / 3
and the base area of a cone is a circle.
the area of a circle is
pi×r²
with r being the radius (again, remember, the radius is half of the diameter). in our case it is therefore 5.5/2 = 2.75 cm.
the volume of the cone here is then
pi×2.75² × 5 / 3 = pi × 12.60416667... cm³ =
= 39.5971574... cm³ ≈ 39.6 cm³