Answer: 45%
Step-by-step explanation: Well in order to get a percent, we need the denominator to be 100 and then the value we get as the numerator is the percentage which we want to calculate.
To get a 100 in the denominator of 9/20, we multiply top and bottom by 5 and we get the equivalent fraction 45/100.
Now the numerator will be our percent which is 45.
So 9/20 is equivalent to 45%.