<em>AC bisects ∠BAD, => ∠BAC=∠CAD ..... (1)</em>
<em>thus in ΔABC and ΔADC, ∠ABC=∠ADC (given), </em>
<em> ∠BAC=∠CAD [from (1)],</em>
<em>AC (opposite side side of ∠ABC) = AC (opposite side side of ∠ADC), the common side between ΔABC and ΔADC</em>
<em>Hence, by AAS axiom, ΔABC ≅ ΔADC,</em>
<em>Therefore, BC (opposite side side of ∠BAC) = DC (opposite side side of ∠CAD), since (1)</em>
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Hence, BC=DC proved.