The volume of a right circular cone is calculated through the equation,
V = πr²h
where V is volume, r is radius of the base, and h is height. Given that height is 3 ft, this can be simplied into,
V = 3πr²
The rate of change with respect to r is,
dV/dr = 6πr
Substituting the DALE,
dV/dr = (6)π(2 m)² = 24π
Answer: 24π.