Answer:
k=4
Step-by-step explanation:
-The constant of proportionality is defined as the ratio between two directly proportional variables.
-Given that B=4f
#The constant of proportionality is calculated as:
- the equation can be written in the form y=kx,
where y varies directly with x and k is the constant of variation:
Hence, B varies directly with f with a constant of proportionality k=4