Answer:
1/16
Explanation:
The equation of a direct proportion is
y = kx
Let amount of fertilizer = y and amount of peat moss = x
We have x = 12 when y = 3/4
3/4 = k * 12
k = (3/4)/12 = 3/4 * 1/12 = 3/48 = 1/16
y = 1/16 x
The constant of proportionality is 1/16.