Final answer:
To find the total number of seventh graders, divide the number of students wearing glasses (100) by the given percentage (25%) represented as a decimal (0.25), which gives us 400 seventh graders in total.
Step-by-step explanation:
To determine the total number of seventh graders based on the given percentage, we can use the following ratio expression: 25% of the total number of seventh graders equals 100 students who wear glasses. This relationship can be represented mathematically as:
0.25 × Total number of seventh graders = 100
To find the total number, we divide 100 by 0.25, which can be mathematically expressed as:
Total number of seventh graders = 100 ÷ 0.25
When we calculate this, we get:
Total number of seventh graders = 400
Therefore, the correct answer is (c)400.