Can someone please help me out
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[tex]BD \: is \: the \: bisector \: of \: \widehat{ABC} \Rightarrow \widehat{ABD}=\widehat{CBD} \\\Rightarrow \widehat{ABC} = \widehat{ABD} + \widehat{CBD} = 2\widehat{ABD} = 2 \times 39 = 78° \\ \Rightarrow D. \: 78° [/tex]