Percentage Discount given an Original Price of $450 and a Sale Price of $360

Discount Rate = 1 –  
Discount Rate = 1 – 0.8
Discount Rate = 0.2
0.2 Converted to a Percent: 0.2 = 20%
Percentage Discount given an Original Price of $450 and a Sale Price of $360 = 20%
Note: Reduction in Price = $450 – $360 = $90