The equation of proportionality is
y = k x, where k is the constant of proportionality
To check the table is in proportion or not let us find the value of k using each line of data, if all of them give the same value of k, then they are proportional
(5, 85)
85 = k(5)
Divide both sides by 5
17 = k
The value of k = 17
let us check the second line
(10, 79)
79 = k(10)
Divide both sides by 10
7.9 = k
Since k has different values, then
Distance to the listener not proportion with the sound level
There is no constant of proportionality