Y is directly proportional to the positive square root of x.

When x = 9, y = 12.

Find y when x = 1/4

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