Answer: We can start by using the proportion method to find the number of girls in the class.
If the ratio of girls to total students is 4:7, that means for every 4 girls, there are 7 students in total. We can set up a proportion:
4/x = 7/21
where x is the number of girls in the class.
To solve for x, we can cross-multiply and get:
4* 21 = 7* x
84 = 7x
Dividing both sides by 7 gives:
x = 12
So there are 12 girls in the class.
Explanation: