Answer:
x = 20
Explanation:
I would say that there are two ways to solve this.
First way:
You could simply this equation be cross multiplying.
4/9 = x/45 → 180 = 9x
Next, divide 180 by 9.
20 = x → x = 20
Second way:
Considering that fraction bars mean division, you could cancel out x/45 by multiplying both fractions by 45.
4/9 = x/45 → 20 = x → x = 20