Final Answer:
The radial acceleration
of the moon in its periodic orbit around the undiscovered planet is approximately

Step-by-step explanation:
To calculate the radial acceleration
we can use the formula for centripetal acceleration:
![\[ a_c = (v^2)/(r) \]](https://img.qammunity.org/2024/formulas/social-studies/high-school/9jymzi5h74uj7ey8yvy0qtrpvhmghocwac.png)
where \(v\) is the tangential velocity and
is the radial distance from the center. First, we need to find the tangential velocity, which can be determined using the formula:
![\[ v = (2 \pi r)/(T) \]](https://img.qammunity.org/2024/formulas/social-studies/high-school/8u780n6u415faj8d7qdxhoy65j1i7f7unq.png)
where T is the period of revolution. Substituting the given values, we find
Now, we can substitute this into the centripetal acceleration formula:
![\[ a_c = ((5.46 * 10^3)^2)/(2.45 * 10^6) \]](https://img.qammunity.org/2024/formulas/social-studies/high-school/ld0zpo1355qy0xlcdx9ykrj2y1b70wpkgg.png)
Solving this expression yields

In summary, the moon's radial acceleration in its periodic orbit around the planet is approximately
This calculation involves the tangential velocity and radial distance, providing insights into the gravitational forces governing the moon's motion.