In the given figure, it is given that AD=BC and AC=BD.
Prove that ∠CAD=∠CBD and ∠ADC=∠BCD.
From the given figure,
In triangles DAC and CBD, we have:
AD = BC
AC = BD
DC = DC
So, by SSS congruence rule
∆ADC ≅ ∆BCD
∴ By Congruent parts of congruent triangles we have:
∠CAD = ∠CBD
∠ADC = ∠BCD
∠ACD = ∠BDC
Hence, proved