Question 979470
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If {{{AC=BC=x}}}, then 
{{{AB=BD=sqrt(2)x}}}
{{{BCD=45}}}
Then use the law of sines,
{{{sin(BDC)/(sqrt(2)x)=sin(45)/x}}}
{{{sin(BDC)=(sqrt(2)/2)/(sqrt(2))}}}
{{{sin(BDC)=1/2}}}
{{{BDC=30}}}
Then,
{{{BDC+DCB+DBC=180}}}
{{{30+45+DBC=180}}}
{{{DBC=180-75}}}
{{{DBC=105}}}