Question

triangleabcand triangle dcb are right angled at a and d respectively and ac=db.prove that triangle abc is comruent to traingle dcb

Answer 1

Draw a circle with bc as diameter.

Chords ac and db are the same length, so the subtend the same central angle. So, ac is parallel to bd, and abcd is a rectangle.

So you have SAS and congruent triangles.