Answer: 9/40
Step-by-step explanation: To write a percent as a fraction in lowest terms, remember that a percent is a ratio that compares a number to 100.
So here, 22.5% can be written as the ratio 22.5 to 100 or 22.5/100.
Notice however that 22.5/100 is not in lowest terms so we need to multiply the numerator and the denominator of 22.5 by 10 in order to remove the decimal point. When we do this, we will end up with the fraction 225/1000.
The fraction 225/1000 can be written in lowest terms by dividing both the numerator and the denominator by 25 and we get the fraction 9/40.
Therefore, 22.5% can be written as the fraction 9/40.