If the third proportional of 40 and Z is 10, then what is the positive value of Z?

Correct option is C

Given:

The first number = 40

The second number = Z

The third proportional = 10

Formula Used:

Third Proportional = $$\frac{Z^2}{40}$$​

Solution:

$$\frac{Z^2}{40} = 10\\ \ \\Z^2 = 10 \times 40\\ \ \\Z^2 = 400$$​

Z = 20