Express the statement as a formula that involves the variables w, z, u and a constant of proportionality k, and then determine the value of k from the condition : w varies directly as z and inversely as the square root of u, if z = 3 and u = 4, then w = 18

w=kz/sqrtU

k=w*sqrt(U)/z= 18*2/3=12? check that.

To express the statement as a formula, we use the concept of direct and inverse variation.

According to the condition, w varies directly as z and inversely as the square root of u. This means that if z increases, w will also increase, and if u decreases, w will increase. Mathematically, we can express this as:

w = k * (z / √u)

Here, k is the constant of proportionality that we need to determine.

Now, we can substitute the given values of z = 3 and u = 4 into the formula to solve for k:

18 = k * (3 / √4)

To simplify further:

18 = k * (3 / 2)

Now, we can solve for k by isolating it:

k = 18 * (2 / 3)

k = 36 / 3

k = 12

Therefore, the value of the constant of proportionality, k, is 12.