Question

By which congruence criteria is ΔABD ≅ ΔACD?

Answer 1

Let, this be figure of a question.

AD is altitude on BC.

In an isosceles triangle altitude, median and angle bisector on non equal sides are same line.

So, AD is also a median.

So, D is midpoint of BC,

⇒BD=CD

AB=AC⋯⋯[given]

And AD=AD⋯⋯[common side]

So, by SSS test

ΔABD≅ΔACD.