Let's denote the number of girls in the class as $g$. According to the problem, there are $\frac{3}{4}$ as many boys as girls, which means the number of boys is:

$b = \frac{3}{4}g$

The total number of students in the class is given as 35. Therefore, we have the equation:

$g + b = 35$

Substitute $b = \frac{3}{4}g$ into the equation:

$g + \frac{3}{4}g = 35$

Combine like terms:

$\frac{4}{4}g + \frac{3}{4}g = 35$

$\frac{7}{4}g = 35$

Multiply both sides by 4 to clear the fraction:

$7g = 140$

Now, divide both sides by 7:

$g = 20$

So, there are 20 girls in the class.

If you'd like more details or have any questions, feel free to ask!

Here are some related questions:

1. How many boys are there in the class?
2. What is the ratio of boys to girls?
3. If 5 more girls join the class, what will be the new ratio of boys to girls?
4. How would the problem change if there were 5 fewer students in total?
5. If there are twice as many boys as girls in another class, how many girls would there be if there were 36 students?

Tip: When dealing with ratios, it's useful to express one quantity in terms of the other and then use given totals to find the values.