Question

in ∆ABC, AB=AC. AB is produced to D such that BD=BC.Prove that ACD=3ADC​

Answer 1

Answer:

since,AB=AC angleACB=angleABC

Now, angleCDB+angleBCD=angleABC

But in ∆CBD angleBCD=angle BDC

Now,angle ACD=angleACB+angleBCD

or angle ACD=angleABC+angleBCD

or angle ACD=angleCDB+angleBCD

+angleBCD

or angle ACD=3ADC

Hence proved.