Answer:
See the diagram
Step-by-step explanation:
[tex]ABC \cong PQR\\\Rightarrow \frac{PQ}{AB} =\frac{PR}{AC}=\frac{QR}{BC} \\\frac{PQ}{AB}=\frac{PR}{AC}\\ \\Since \ AB=AC\\PQ=PR\\PR=8cm\\\\\frac{PQ}{AB}=\frac{QR}{BC}\\\\QR=\frac{PQ}{AB} \cdot BC\\\\QR=\frac{8}{6} \cdot 5\\\\QR=\frac{20}{3}[/tex]