$\begin{array}{l}
\mathop {\,{\rm{A}}}\limits^ \to  \,\, + \;\,\mathop {\rm{B}}\limits^ \to  \,\, + \,\,\mathop {\rm{C}}\limits^ \to  \, = \,\,\mathop 0\limits^ \to  \, \Rightarrow \,\,\mathop {\,{\rm{A}}}\limits^ \to  \,\, + \;\,\mathop {\rm{B}}\limits^ \to  \,\, =  – \,\,\mathop {\rm{C}}\limits^ \to  \\
{A^2}\,\, + \;\,{B^2}\,\, + \;\,2AB\cos {\theta _1}\,\, = \,\,{C^2}\,\,\left( {\,\,A\,\, = \,B} \right)\\
{B^2}\,\, + \;\,{B^2}\,\, + \;\,2AB\cos {\theta _1}\,\, = \,\,2{B^2}\,\,\left( {\,\,C\,\, = \,\,\sqrt 2 B} \right)\\
2AB\cos {\theta _1}\,\, = \,\,0\,\, \Rightarrow \,\,\cos {\theta _1}\,\, = \,\,0\,\, \Rightarrow \,\,{\theta _1}\,\, = \,\,90^\circ \\
\mathop {\rm{B}}\limits^ \to  \,\, + \,\,\mathop {\rm{C}}\limits^ \to  \,\, = \,\, – \mathop {\rm{A}}\limits^ \to  \,\, \Rightarrow \,\,{B^2}\,\, + \;\,{C^2}\,\, + \;\,2BC\,\,\cos {\theta _2}\,\, = \,\,{A^2}\\
{B^2}\,\, + \;2{B^2}\,\, + \;\,2B\sqrt 2 \,B\cos {\theta _2}\,\, = \,\,{B^2}\\
2{B^2}\,\,\left( {1\, + \,\,\sqrt 2 \cos {\theta _2}} \right)\,\, = \,\,0\,\, \Rightarrow \,\,\cos {\theta _2}\,\, = \,\, – \frac{1}{{\sqrt 2 }}\,\, \Rightarrow \,\,{\theta _2}\,\, = \,\,135^\circ \\
\therefore \,\,\left( {90^\circ ,\,135^\circ ,135^\circ } \right)
\end{array}$ ખૂણાઓ છે