Answer:
y = 2
Step-by-step explanation:
from the question which says that y is directly proportional to the positive square root of x can be expressed mathematically by saying
y ∝ √x
y = k√x..................................................... where k is the constant of proportionality.
y = 12, x = 9 , k = ?
from
y = k√x
12 = k√9
12 =3k
divide both sides by the coefficient of k which is 3
12/3 = 3k/3
4 = k
therefore K = 3
now, to find the value of y when x = 1/4
from y = k√x
y = 4√1/4
y = 4 × 1/2
y = 2
therefore the value of y when x = 1/4 in this expression y = k√x is 2