First, we find the ratio between the triangles by just dividing side
[tex]\frac{20}{12}=\frac{5}{3}[/tex]
Then, we find n multiplying 8 by the scale factor
[tex]\begin{gathered} n=18\cdot\frac{5}{3} \\ n=6\cdot5 \\ n=30 \end{gathered}[/tex]
Hence, the answer is 30.
