[tex]\it \mathcal{A}=\dfrac{AB\cdot AC\cdot sinA}{2} =\dfrac{12\cdot12sinA}{2}=72sinA\\ \\ Dar,\ \ \mathcal{A}=36,\ \ deci:\\ \\ 72sinA=36 \Rightarrow sinA=\dfrac{\ 36^{(36}}{72} \Rightarrow sinA=\dfrac{1}{2} \Rightarrow \widehat {A}=30^o[/tex]
[tex]\it \Delta ABC\ -\ isoscel,\ AB=AC \Rightarrow \hat B=\hat C=\dfrac{180^o-30^o}{2}=75^o[/tex]
