Consider Δ ABC. If ADDB=AEEC and ∠ ADE = ∠ ACB. Then Δ ABC is an equilateral triangle.
False
Since, ADDB=AEEC (Given)
So by Converse of Basic Proportionality theorem,
DE∥BC
Given, ∠ ADE = ∠ ACB ---- (1)
Also, ∠ ADE = ∠ ABC ----- (2) [Transverse angles in parallel lines are equal]
From (1) and (2),
⇒∠ABC=∠ACB
Hence, it is an isosceles triangle.