A simple pendulum has a period of $4$ seconds when measured on Earth where the gravitational acceleration is $9\mathrm{.}81\frac{m}{s^2}.$ The period of the pendulum when measured on Planet $x$ is $3$ seconds. What is the gravitational acceleration on Planet $x?$

$17\mathrm{.}4\frac{m}{s^2}$

$3\mathrm{.}36\frac{m}{s^2}$

$5\mathrm{.}52\frac{m}{s^2}$

$11\mathrm{.}1\frac{m}{s^2}$

$9\mathrm{.}81\frac{m}{s^2}$