"Quarter" have other popular usages that are deeply ingrained in American culture. "Quarterback", "Insert a quarter", "This quarter's results were good", "quart

"Quarter" have other popular usages that are deeply ingrained in American culture. "Quarterback", "Insert a quarter", "This quarter's results were good", "quart" (measurement), "it's a quarter to one" etc. Actual math aside, it's simply a more familiar word.