In both triangles, one angle is 90 degrees.
Another angle of both the triangles is shown to be equal.
Since two angles of both the triangles are equal , the third angle of both the triangles are also equal.
As all the angles of two triangles are equal, the triangles are similar.
For similar triangles, the ratio of the corresponding sides of the triangles are equal.
So, we can write
[tex]\begin{gathered} \frac{x}{48\text{ }}=\frac{20\text{ }}{80\text{ }} \\ x=\frac{20}{80}\times48 \\ x=12 \end{gathered}[/tex]Therefore, the value of x is 12.