In a right - angled triangle PQR, ∠Q is right angled, and S is a point on the side PQ. Find the value of PS.

In a right - angled triangle PQR, ∠Q is right angled, and S is a point on the side PQ. Find the value of PS. Correct Answer √{RS<sup>2</sup> – PR<sup>2</sup> + (2 × PQ × PS)}

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In ΔPQR:

PR2 = PQ2 + QR2

QR2 = PR2 – PQ2           ----(1)

In ΔSQR:

RS2 = QS2 + QR2

QR2 = RS2 – QS2           ----(2)

From (1) and (2):

PR2 – PQ2 =  RS2 – QS2

QS2 = RS2 + PQ2 – PR2

(PQ – PS)2 = RS2 + PQ2 – PR2

PQ2 + PS2 – (2 × PQ × PS) = RS2 + PQ2 – PR2

PS2 = RS2 – PR2 + (2 × PQ × PS)

PS = √{RS2 – PR2 + (2 × PQ × PS)}

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