$\overset{\vartriangle }{\mathop{oMH}}\,$ مثلث $:\widehat{H}=90{}^\circ ,\widehat{o}=51{}^\circ \Rightarrow \widehat{M}=180-\left( \overset{141}{\mathop{\not{90+51}}}\, \right)=39{}^\circ $ $\overset{\vartriangle }{\mathop{oHN}}\,$ مثلث $\widehat{H}=90{}^\circ ,\widehat{o}=67{}^\circ \Rightarrow \widehat{N}=180{}^\circ -\left( \overset{157}{\mathop{\not{90{}^\circ +67{}^\circ }}}\, \right)=23{}^\circ $ $\widehat{M}-\widehat{N}=39{}^\circ -23{}^\circ =16{}^\circ $