[tex]AC\text{ = 16}[/tex]
When two triangles are similar, the ratio of their corresponding sides are equal
Thus, we have it that;
[tex]\begin{gathered} \frac{AB}{AC}\text{ = }\frac{PQ}{PR} \\ \frac{20}{AC}\text{ = }\frac{50}{40} \\ \\ AC\text{ = }\frac{40\times20}{50}\text{ = 16} \end{gathered}[/tex]
