When does the shape of the moon appears to be perfectly round?

Explanation

To determine when the shape of the moon appears to be perfectly round, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Lunar Phases**: The moon goes through different phases as it orbits the Earth. These phases are caused by the relative positions of the Earth, moon, and sun.

2. **Identifying the Full Moon**: The phase when the moon appears fully illuminated is known as the "full moon." This is the time when the entire face of the moon that is visible from Earth is lit up by the sun.

...