Q87 of 131 Page 226

In Fig. 9.41, area of ∆PQR is 20 cm2 and area of ∆PQS is 44 cm2. Find the length RS, if PQ is perpendicular to QS and QR is 5cm.

We know that, Area of triangle = × b × h


Area of ∆PQR = 20 cm2


× QR × PQ = 20


× 5 × PQ = 20


∴ PQ = 8 cm


Area of ∆PQS = 44 cm2


× QS × PQ = 44


× QS × 8 = 44


∴ QS = 11 cm


RS = QS – QR = 11 – 5 = 6 cm


Length of RS = 6 cm


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