Answer:
16π units
Explanation:
The formula for the volume of a cone is V = (1/3)πr^2h, where r is the radius of the circular base and h is the height of the cone.
In this problem, we know that the volume of the cone is 448π cubic units and the height is 21 units. We can use this information to solve for the radius of the cone as follows:
V = (1/3)πr^2h
448π = (1/3)πr^2(21)
448 = 7r^2
r^2 = 64
r = 8
So the radius of the circular base of the cone is 8 units.
To find the circumference of the base of the cone, we can use the formula for the circumference of a circle, which is C = 2πr.
C = 2π(8) = 16π
Therefore, the circumference of the base of the cone is 16π units.