Question

16. In a triangle ABC, AB=AC, AB is produced
to D such that BD=BC. Prove that ZACD
= 3 ZADC
Please answer this guys ​

Answer 1

Answer:

In ∆ABC , AC = AB

So, ∠ACB = ∠ CBA = α

∠BAC = 180°-2α

In ∆CBD , BC = BD

So, ∠CBD = 180°-α

∠BCD = ∠BDC = α/2

Now,

∠ACD = ∠ACB + ∠BCD = α+α/2 = 3α/2

∠ADC = ∠BDC = α/2

SO, ∠ACD = 3∠ADC

• Hence proved.