The correct option is
C 6.8 cm
As the triangles are similar, so their corresponding sides are in the same ratio.
Here, vertex
A corresponds to vertex
P.
Given:
AB=4 cm,BC=8 cm,AC=9 cm and
PQ=1.6 cm.
So,
ABPQ=BCQR=ACPR
⇒ 41.6=8QR=9PR
⇒ QR=3.2 cm
And,
PR=92.5=3.6 cm
So,
QR+PR=3.2+3.6=6.8 cm
Hence, option
(c) is correct.