Vì $ΔABC=ΔDHK$
$→ \widehat{A}=\widehat{D}; \widehat{B}=\widehat{H}; \widehat{C}=\widehat{K}$
Ta có: $\widehat{B}=35^{0}$
$→\widehat{H}=35^{0}$
Ta có: $\widehat{K}=100^{0}$
$→\widehat{C}=100^{0}$
Ta có: $\widehat{A}+\widehat{B}+\widehat{C}=180^{0}$
$→\widehat{A}=180^{0}-(\widehat{B}+\widehat{C})=180^{0}-(35^{0}+100^{0})=180^{0}-135^{0}=45^{0}$
Ta có: $\widehat{A}=45^{0}$
$→\widehat{D}=45^{0}$