Use a proportion to answer the question.

21 is 4% of what number?

21.875???

21/x = 4/100

4x = 2100

x = 525

Thank you

To find the number that 21 is 4% of, we can set up a proportion.

Let's assume the unknown number is represented by 'x'.

The proportion can be set up as:

21 / x = 4 / 100

To solve for 'x', we cross-multiply and then divide:

21 * 100 = 4 * x

2100 = 4x

Dividing both sides by 4:

x = 2100 / 4

Simplifying the division:

x = 525

Therefore, 21 is 4% of the number 525.

So your answer is 525.