Question

Please answer who is genius

Answer 1

i tri. DEC and DCF
DC= DC. (common)
DE=DE. (given)
angle dec = angle DFC. (given)
so by SAS congruency criterion tri.
dec congruent dcf

Answer 2

Given: ABC is a triangle, CD is altitude and DE and DF are prependiculars from D on the sides AC and BC and DE = DF.

To proof : triangle-DEC = triangle-DFC

Prove: In triangle-DEC and triangle-DFC
DE =DF (Given)
DC = DC (Common)
angle DEC = angle DFC = 90degree (Given)

Hence,

triangle-DEC = triangle-DFC (RHS congruence criterion)

Hence Proved

Hope this helps you...:)