In the given figure, \(E\) lies on the extension of side \(CB\) of an isosceles triangle \(ABC\) where \(AB=AC\). If \(AD⊥BC\) and \( EF⊥AC\). Derive that \( △ADB∼△ECF\).
 
YCIND_240214_6037_a_42.png
 
 
In isosceles triangle \(ACB\),
 
where \(AB = AC\)
 
Angles opposite to equal sides are equal.
 
\(\angle C = \angle\) - - - - (1)
 
 In \(\Delta ABD\) and \(\Delta ECF\),
 
\(\angle ABD = \angle\)  (from (1))
 
\(\angle ADB = \angle\) (Both \(90^\circ\))
 
Thus, \(\Delta ABD \sim \Delta ECF\) (by similarity)
 
Hence proved.