What significant action did the 1788 convention in Augusta take regarding the state charter?

The significant action taken by the 1788 convention in Augusta was the decision to discard the existing state charter and create a new constitution. This was a pivotal moment in Georgia's history as it marked a shift in governance following the principles laid out in the U.S. Constitution. The decision to create a new constitution reflected the acknowledgment that the old charter was inadequate for the newly established framework of government following the American Revolution.

This move was influenced by the need for a more robust and systematic form of governance that addressed the evolving needs of the state and its citizens, as well as aligning with the federal model. The new constitution introduced changes that aimed to improve governance, reflect democratic ideals, and provide a clearer structure for the state's legislative, executive, and judicial branches.

In contrast, the other options do not accurately represent the actions taken at the convention. For instance, adding amendments would imply that the existing charter was sufficiently functional, which was not the view of the delegates. Adjusting it with minor changes or seeking modifications from the federal government would not capture the transformative intent of this particular convention, which sought to fundamentally redefine governance in Georgia through a completely new legal document.