Convert the percentage to a decimal by dividing by 100
Divide the part by the decimal
Use the formula: Whole = Part ÷ Percentage as a decimal
Example: if 25 is 20%, then Whole = 25 ÷ 0.20 = 125
If the percentage is a fraction of a whole, use: Whole = Part × 100 ÷ Percentage
Example: if 30 is 15%, then Whole = 30 × 100 ÷ 15 = 200