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In the given figure, AD = AE and AD^2 = BD x EC. Prove that: triangles ABD and CAE are similar.

Selina Solutions Concise Class 10 Maths Chapter 15 ex. 15(A) - 10

Answer:

In \[\Delta \text{ }ABD\text{ }and\text{ }\Delta \text{ }CAE,\]

\[\angle ADE\text{ }=\angle AED\text{ }\left[ Angles\text{ }inverse\text{ }to\text{ }rise\text{ }to\text{ }sides\text{ }are\text{ }equal. \right]\]

In this way, \[\angle ADB\text{ }=\angle AEC\]\[[As\text{ }\angle ADB\text{ }+\text{ }\angle ADE\text{ }=\text{ }{{180}^{o~}}and\text{ }\angle AEC\text{ }+\text{ }\angle AED\text{ }=\text{ }{{180}^{o}}]\]

Furthermore, \[A{{D}^{2}}\text{ }=\text{ }BD\text{ }x\text{ }EC\][Given]

\[AD/\text{ }BD\text{ }=\text{ }EC/\text{ }AD\]

\[AD/\text{ }BD\text{ }=\text{ }EC/\text{ }AE\]

Along these lines, \[\vartriangle ABD\text{ }\sim\text{ }\vartriangle CAE\]by \[SAS\]rule for similitude.