Q90 of 131 Page 226

Area of a triangle PQR right-angled at Q is 60 cm2 (Fig. 9.43). If the smallest side is 8cm long, find the length of the other two sides.


Given, area of ∆PQR = 60 cm2 with PQ = 8 cm


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


Area of ∆PQR = 60 cm2


× PQ × QR = 60


× 8 × QR = 60


∴ QR = 15 cm


Applying Pythagoras theorem in ∆PQR,


(PQ)2 + (QR)2 = (PR)2


(8)2 + (15)2 = (PR)2


(PR)2 = 64 + 225 = 289


AC =√289 = 17 cm


Hence, the length of two sides are 15 cm and 17 cm.


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