Answer: The required ratio is PT:TR = 1:2.
Explanation:
Given: In triangle PQR, ST || QR, PT = 4cm, TR = 8cm, area of PQR = 90 cm².
To find : PT:TR
.i.e. Ratio of PT to TR.
Here, PT:TR


Divide numerator and denominator by 4 , we get

Therefore, the required ratio is PT:TR = 1:2.