1994 年

In the figure, $ABCD$ is a semi-circle, $CDE$ and $BAE$ are straight lines. If $\angle CBD=30^\circ$ and $\angle DEA=22^\circ$, find $x$.

In the figure, $OABCD$ is a sector of a circle. If $\overset{\frown}{AB}=\overset{\frown}{BC}=\overset{\frown}{CD}$, then $x=$

In the figure, $AB\parallel DC$ and $\angle DAB=\angle DBC$. Which of the following is/are true?

I. $\dfrac{AB}{BD}=\dfrac{BD}{DC}$ II. $\dfrac{AB}{BD}=\dfrac{AD}{BC}$ III. $\dfrac{AD}{BD}=\dfrac{BD}{CD}$