2009 年

In the figure, $G$ is the centroid of $\triangle ABC$. $AG$, $BG$ and $CG$ are produced to meet $BC$, $AC$ and $AB$ at $L$, $M$ and $N$ respectively. If $BL=13\text{ cm}$, $BN=5\text{ cm}$ and $CM=12\text{ cm}$, find the area of $\triangle ABC$.

The coordinates of two vertices of a triangle are $(-4,-8)$ and $(6,2)$. If the coordinates of the circumcentre of the triangle are $(k,-4)$, then $k=$

In the figure, the circle touches the positive $x$-axis and the positive $y$-axis. The coordinates of the points $A$ and $B$ are $(21,0)$ and $(0,28)$ respectively. If $AB$ passes through the centre of the circle, find the equation of the circle.

The broken line graphs below show the annual revenue (in million dollars) of Company $X$ and Company $Y$ in 2008 and 2009.

Which of the following statements about the percentage increases of the annual revenue of the two companies from 2008 to 2009 is true?