The mean proportional of 8a² and 18over a⁴ , where a is a positive number, is ____.

The mean proportional of 8a² and 18over a⁴ , where a is a…

The mean proportional of 8a² and $18\over a^4$ , where a is a positive number, is ____________.

Show answer & explanation

Correct answer: D

Explanation

The correct answer is Option 4 i.e. $12\over a$ .

We know that,

Mean proportional = $\sqrt{xy}$

⇒ $\sqrt{8a^2 \times {18\over{a^4}}}$

⇒ $\sqrt{144\over a^2}$ = $12\over a$