In ΔPQR, S and T are points on PQ and PR, respectively, such that ST ∥ QR and ST divides the ΔPQR into two parts of equal areas. Then the ratio of PS and QS is:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. .
We know,
The ratio of the area of similar triangle = (Ratio of corresponding sides)2
Now,

ST || QR and ST divide triangle PQR into two parts of equal areas, area of triangle PST is half of the area of triangle PQR
Let the ratio of the areas be 1 : 2
The ratio of their respective sides, PS : PQ = 1 : √2
⇒ PQ = PS + QS
Let the value of PS and PQ be x and √2x
⇒ PQ = x + QS
⇒ PS/PQ = 1/√2
⇒ x/(x + QS) = 1/√2
⇒ √2x = x + QS
⇒ QS = (√2 - 1)x
Hence, the required ratio of PS : QS = x : (√2 - 1)x
⇒ 1 : (√2 - 1)