D18 did a BFA (albeit in ballet not acting) and one of the possibilities for her BS was math (though she eventually chose environmental studies). At most universities math is a relatively light major, typically 50-55 semester credits, unlike the 65-70 or so typical of engineering and without any of the labs needed for most science subjects. So it’s at least somewhat easier to fit around a fixed performing arts schedule.
She did finish in 4 years at Utah (with >3.9 GPA), but had to take about 155 semester credits total, ie equivalent to just over 5 years at the typical rate of 30/year: roughly 80 for the BFA, 50 for the BS and 25 for Gen Ed/Honors/thesis (in addition to getting exemptions from another ~15 Gen Ed credits with APs). Fortunately Utah was perfectly ok with her taking 22-23 credits per semester for most of her time there, and it was relatively straightforward to fit the BS courses around ballet classes. It also has a pretty strong math department.