To determine what percent 21 is of 75, we can set up a proportion. The formula for finding a percentage is:
\[ \text{Percentage} = \left(\frac{\text{Part}}{\text{Whole}}\right) \times 100 \]
In this case, we have:
- Part = 21
- Whole = 75
We can set up the proportion as follows:
\[ \frac{21}{75} = \frac{x}{100} \]
where \(x\) represents the percentage we are trying to find. Now we can cross-multiply to solve for \(x\):
\[ 21 \times 100 = 75 \times x \]
This simplifies to:
\[ 2100 = 75x \]
Next, solve for \(x\) by dividing both sides by 75:
\[ x = \frac{2100}{75} \]
Calculating the right side:
\[ x = 28 \]
So, 21 is 28% of 75.
Answer: 28%