CODEWITHSUNDEEP
javascript
methuselah
methuselah

Reputation: 13206

Calculate unknown total with amount of the percentage

I have two values

startWidth = 500px
percentageWidth = 70%

I'd like to calculate the value of startWidth at when percentageWidth changes, for example if I wanted maxWidth, I'd be working with:

startWidth = ???px
percentageWidth = 100%

To calculate this mathematically is easy, I would just do:

  1. Create an equation that shows the fractional relationship between the percentage and its value. Use the variable x to represent the unknown total.
70/100 = 500/x
  1. Cross-multiply the equation to bring the variable to one side of the equation as a whole number. Multiply values diagonal from each other in the equation, i.e.
70x = 50000
  1. Divide both sides by the coefficient 70
70x/70 = 50000/70
x = 714

How would I write this out as a JavaScript algorithm?

Upvotes: 0

Views: 107

Answers (1)

DecPK
DecPK

Reputation: 25408

You can easily achieve the result as

const startWidth = 500;
const percentageWidth = 70;

const result = Math.round((startWidth * 100) / percentageWidth);
console.log(result);

Upvotes: 1

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