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如图,将\(\triangle ABC\)沿着射线\(BC\)方向平移至\(\triangle A{{'}}B{{'}}C{{'}}\),使点\(A{{'}}\)落在\(∠ACB\)的外角平分线\(CD\)上,连结\(AA{{'}}\).
\((1)\)判断四边形\(ACC{{'}}A{{'}}\)的形状,并说明理由;
\((2)\)在\(\triangle ABC\)中,\(∠B=90^{\circ}\),\(AB=24\),\(\cos ∠BAC= \dfrac {12}{13}\),求\(CB{{'}}\)的长.