Answer :

To arrange the numbers 1, 2, 3, 4, 5, 6, and 7 on a beach ball so that every possible line sums to the same total can be a complex and exploratory task.

Here are the sums of various combinations based on a theoretical arrangement of the numbers:
1. The sum of the first, second, and third numbers is 11.
2. The sum of another combination, possibly involving different positions such as the fourth, second, and fifth numbers, is 6.
3. Another combination of these numbers gives us 16.
4. Yet another distinct combination of the numbers yields a sum of 15.
5. One more distinct grouping of the numbers results in a sum of 9.
6. The final combination of certain numbers sums to 13.

In this arrangement, it is evident that the total sum for every line does not necessarily add up to the same number in this case.

To find an arrangement where every line adds up to the same total is quite challenging and may require using some specific strategy or algorithm, but the example provided does not directly lead us to such an arrangement.

The essential insight learned here is that it is crucial to explore different combinations of the numbers to achieve a configuration where every line's sum is equal, showing the beauty and complexity inherent in arranging numbers to meet specific criteria. This exercise demonstrates the intricacies of combinatorial arrangements and the necessity of systematic experimentation or advanced mathematical concepts to resolve the challenge accurately.