The lengths of th

One of the length should be 35cm.

So, for perimeter to be greatest the smallest length of PQR should be 35 cm so that the other 2 sides could be greater than 35 cm hence greatest Perimeter achieved in that case.

ΔPQR ∼ ΔABC (given)

⇒ PQ = 35 cm (∵ It corresponds AB which is the smaller side of ΔABC)

⇒ PR = 52.5 cm

⇒ QR = 78.75 cm

⇒ Perimeter = PQ + PR + QR

⇒ Perimeter = 35 + 52.5 + 78.75

⇒ Perimeter = 166.25 cm