Question

Two numbers are x and 4x, and their mean proportional is 456976. Find x.

• A. 228848
• B. 288488
• C. 228488
• D. 228448

Answer 1

Answer:

C. 228488

The mean proportional between two numbers (a) and (b) is:

$\sqrt{ab}$

Here the numbers are x and 4x.

$\text{Mean proportional} = \sqrt{x \cdot 4x}$
$= \sqrt{4x^2}$
$= 2x$

Given:
$2x = 456976$
$x = \frac{456976}{2}$
$x = 228488$

Final Answer: x = 228488