The percentage discount is the reduction in price divided by the original price. The difference between original price and sale price is:
9.20 − 5.06 = 4.14
The percentage discount is this difference divided by the original price:
4.14 ÷ 9.20 = 0.45
Convert the decimal to a percentage by multiplying by 100%:
0.45 × 100% = 45%