⓵ You need to use what we call a cross product. This method is also also known as cross multiplication. Let me show you an example :
Say you had 17/20 in a test and you really want to know what percentage that represents.
17 / 20 = × / 100
I then like to change the writing form to visual everything better :
17 → 20
× → 100
And then I transform this proportion into an equation to solve it :
(17 x 100) ÷ 20 = ×
↓
1700 ÷ 20 = ×
↓
85 = ×
So 17/20 turns out to be equal to 85/100 which is 85%!
I hope this helped, if there’s anything just let me know! ☻