Q10 of 186 Page 229

In the given figure, DE || BC. If DE = 3 cm, BC = 6 cm and ar (ΔADE) = 15 cm2, find the area of ΔABC.

It is given that DE || BC


∴∠ ADE = ∠ ABC (Corresponding angles)


∠ AED = ∠ ACB (Corresponding angles)


So, by AA similarity criterion ΔADE ~ ΔABC


We know that if two triangles are similar then the ratio of their areas is equal to the ratio of the squares of their corresponding sides.





Hence, proved.


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