Question

If y varies directly as the square root of x, and v = 9 when x = 81 , find y when x = 9

A.81
B.27
C.3
D.1

Answer 1

the answer is C. 3.

Explanation:

If y varies directly as the square root of x, then we can write an equation in the form y = k*sqrt(x), where k is a constant of proportionality.

To find the value of k, we can use the given information that v = 9 when x = 81:

9 = ksqrt(81)

9 = k9

k = 1

So the equation for y is y = sqrt(x).

Now we can find y when x = 9:

y = sqrt(9)

y = 3

Therefore, the answer is C. 3.