Step 1 :The problem is asking for the proportion of tenth graders reading at or below the eighth grade level. We know that out of 310 students, 255 read above the eighth grade level.
Step 2 :Therefore, the number of students reading at or below the eighth grade level would be the total number of students minus the number of students reading above the eighth grade level. So, \(310 - 255 = 55\) students read at or below the eighth grade level.
Step 3 :To find the proportion, we would then divide the number of students reading at or below the eighth grade level by the total number of students. So, \(\frac{55}{310} = 0.1774193548387097\).
Step 4 :Rounding to three decimal places, we get 0.177.
Step 5 :Final Answer: The proportion of tenth graders reading at or below the eighth grade level is approximately \(\boxed{0.177}\).