Given that two figures are similar, use a scale factor to find the missing length

The missing length x is 99 m.
Solution:
Given polygons are similar.
If two triangles are similar, then the corresponding sides are in proportion.
[tex]$\Rightarrow\frac{81}{18}=\frac{x}{22}[/tex]
Multiply by 22 on both sides, we get
[tex]$\Rightarrow\frac{81}{18}\times 22=\frac{x}{22}\times 22[/tex]
[tex]$\Rightarrow\frac{9}{2}\times 22=x[/tex]
⇒ 9 × 11 = x
⇒ 99 = x
Switch the sides.
⇒ x = 99
The missing length x is 99 m.