6. In the diagram, $\triangle A B C$ and $\triangle C D E$ are equilateral triangles. Given that $\angle E B D=62^{\circ}$ and $\angle A E B=x^{0}$, what is the value of $x$ ?
(A) 100 ;
(B) 118 ;
(C) 120;
(D) 122 ;
(E) 135 .
6. Ans: (D)
Observe that $\triangle B C D$ is congruent to $\triangle A C E$ (using $\mathrm{SAS}, B C=A C, C D=C E$ and $\angle A C E=$ $60^{\circ}-\angle E C B=\angle B C D$ ). Thus $\angle A E C=\angle B D C$. We get
$$
\begin{aligned}
x^{\circ} & =360^{\circ}-\angle A E C-\angle B E C \\
& =360^{\circ}-\angle B D C-\angle B E C \\
& =\angle E B D+\angle E C D \\
& =62^{\circ}+60^{\circ}=122^{\circ}
\end{aligned}
$$

Thus $x=122$.