Question

If 4, x, x and 49 are in proportion, find the value of x.

• A. 7
• B. 14
• C. 21
• D. 35

Answer 1

The correct option is B

14

$\text{Given:}4,x,x,49\text{are in proportion i.e.}4:x::x:49$
$\Rightarrow \frac{4}{x}=\frac{x}{49}$
$\Rightarrow x\times x=4\times 49$
$\Rightarrow x\times x=196$
$\Rightarrow x\times x=14\times 14$
$\Rightarrow x=14$