600 sixth-graders were surveyed.
Step-by-step explanation:
Step 1; Assume x is the total number of sixth-graders that were surveyed. According to the given circle graph, 5% of the sixth-graders that were surveyed have birds as their pets. If x is the total number of sixth-graders surveyed then 5% of x equals 30. So
5% of x = 30.
5% equals = 0.05, so 5% = 0.05.
Step 2; If 0.05 x = 30, we can solve by keeping the unknown value on one side and keeping all the known values on one side.
x = = 600.
So 600 sixth-graders were surveyed.