This kind of question is a "number is what percent of number" problem.
To solve this, divide the first number (22.5) by the second number (90) and multiply by 100.
22.5 / 90 = 0.25
0.25 • 100 = 25
So 22.5 is 25% of 90.
You can check this by doing 0.25, or just 25%, times 90.
0.25 • 90 = 22.5
This clarifies that 25% is the correct answer.
