The ratio between corresponding sides are the same for all pairs of corresponding sides in similar figures.
x=22.5
We are told that the polygons are similar, and we want to find the value of x.
Since the figures are similar, their corresponding sides are also similar. Let's identify corresponding sides on the diagram.
The ratio between corresponding sides is the same for all pairs of corresponding sides.
4/9=8/18=10/x
We can use the first and the third ratio to solve for x.