G2.3 In Figure 2, there is a circle with centre $O$ and radius $r$. Triangle $A C D$ intersects the circle at $B, C, D$ and $E$. Line segment $A E$ has the same length as the radius. If $\angle D A C=20^{\circ}$ and $\angle D O C=x^{\circ}$, find the value of $x$.
$\begin{array}{l}\angle A O E=20^{\circ}(\text { Given } A E=O E, \text { base } \angle \text { s isos. } \triangle) \\ \angle O E D=20^{\circ}+20^{\circ}=40^{\circ}(\text { ext. } \angle \text { of } \triangle A O E) \\ \angle O D E=\angle O E D=40^{\circ}(\text { base } \angle \text { s isos. } \triangle) \\ x=20+40=60(\text { ext. } \angle \text { of } \triangle A O D)\end{array}$