Answer: The answer is approximately 21%.
Step-by-step explanation: Given that in Wally's school, there are total 283 students, out of which 59 students are in the sixth grade. We are to calculate approximately the percentage of students in the sixth grade.
To find the required percentage, we will divide the number of students in the sixth grade to the total number of students and then multiply by 100%.
Therefore, the percentage is

Thus, the required percentage is approximately 21%.