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Find area of parrellogram ABCD whose adjacent sides are 60 cm, 40 cm and one diagonal is 80 cm find area? |
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Answer» Let ABCD is a parallelogram in which AB= DC= 100 cm. and BC =AD= 60 cm.,diagonal DB= 80 cm.In triangle DAB , DA^2+DB^2= (60)^2+(80)^2= 3600+6400 = 10000……….(1)and (AB)^2= (100)^2= 10000………………….(2). From eqn. (1) and (2)DA^2+DB^2=AB^2. , THEREFORE. Angle ADB= 90°.Area of parallelogram ABCD = 2×Area of right angled triangle ADB.= 2×1/2.(DA×DB)= 60 cm× 80 cm= 4800 cm^2. |
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