Thanks for taking the time to post your question!
I think there are two ways to think about this … one would be in relation to the maximum GPA, which is typically a 4.00 GPA.
In that scenario the percentage would be found by taking
(GPA/Maximum GPA) * 100
=2.26 / 4.00 * 100
=56.5%
As in you have logically received 56.5% of the maximum available grade point average points.
It might be more helpful though to think of the 2.26 GPA as translating to a letter grade. Depending on the scale a 2.26 GPA would typically be a C or C+, which means a grade of around 75%.
Hope that helps :)
