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if $$AB=AC=EF,AE=BE,\angle BAC=120^{\circ},\angle ADB=\angle BEF=90^{\circ}$$
find $\angle ABE$
Following is one methods
Let $\angle ABE=a,\angle AFE=\angle DBE=\dfrac{\pi}{6}-a,\angle EAF=\dfrac{\pi}{3}-a$ use sine thereom we have
$$\dfrac{\sin{a}}{\sin{(\pi-2a)}}=\dfrac{AE}{AB}=\dfrac{AE}{EF...