After each cut, the remaining area is 80% of the previous area.
Step-by-step explanation:
The original area is 100 cm^2. After the first cut the remaining area is 80 cm^2, that is, 80 cm^2/(100 cm^2)*100 = 80% of the previous. The 80% of 80 cm^2 is 0.8*80 = 64 cm^2, which is the remaining area after the second cut. The 80% of 64 cm^2 is 0.8*64 = 51.2 cm^2, which is the remaining area after the third cut. And so on.