Answer:
The answer to your question is: 2.29 units
Step-by-step explanation:
Data
Volume = 16π
radius = ?
Formula
V = 
Process
16 π = 

r³ = 12
r = 2.29
If we call the number "x" then:
x*25%=21
x*25/100=21
x=21*4
x=84
The constant of proportionality is the ratio between two directly proportional quantities. Two quantities are directly proportional when they increase and decrease at the same rate. The constant of proportionality k is given by k=y/x where y and x are two quantities that are directly proportional to each other.
Answer:
I think option B is correct