2005 年

In the figure, $\theta$ is an acute angle. Find $\theta$ correct to the nearest degree.

In the figure, $\cos\theta=$

In the figure, $ABCD$ is a rectangle. If $BED$ is a straight line, then the area of $\triangle ABE$ is

In the figure, $ABCD$ is a circle. $AB$ produced and $DC$ produced meet at $E$. If $AC$ and $BD$ intersect at $F$, then $\angle ABD=$

In the figure, $ABCD$ is a circle. If $AC$ is a diameter of the circle and $AB=BD$, then $\angle CAD=$

If $AC=BD$ and $AB\parallel DC$, how many pairs of similar triangles are there in the figure?

In the figure, $ABCD$ is a square. If $CEF$ is an equilateral triangle, then $\angle CBF=$

In the figure, $x=$

In the figure, $OABC$ and $OFED$ are straight lines. If $AB:BC=2:3$ and $FA:DC=1:5$, then $OA:AB=$

In the figure, the length of the line segment joining $A$ and $F$ is