Question

If$x,y$ and $z$ are in proportion, then

• A. $x^2=yz$
• B. $y^2=xz$
• C. $z^2=xy$
• D. $x=y=z$

Answer 1

The correct option is B

$y^2=xz$

If three numbers are in proportion then the ratio of the first two = ratio of the last two

$$\begin{gathered} x:y=y:z \\ \frac{x}{y}=\frac{y}{z} \\ xz=y^2 \end{gathered}$$

So option (B) is the answer.

Explanation for incorrect option:

Option(A) is incorrect option because numbers are in the order y,x,z according to this option. But numbers are given in the order x,y,z.

Option(C) is incorrect option because numbers are in the order x,z,y according to this option. But numbers are given in the order x,y,z.

Option(D) is incorrect option because equality or non-inequality about numbers is not given.