## University Calculus: Early Transcendentals (3rd Edition)

$\overline{x}=\dfrac{a}{3}$ and $\overline{y}=\dfrac{a}{3}$
We notice that the triangle with vertices $(0,0), (a,0), (0,a)$ has the x-coordinate a third of the distance $(a,0)$ from the edge, which corresponds to the $y$-axis. Also, the y-coordinate is a third of the distance of $(0,a)$, which corresponds to the $x$-axis. This means that $\overline{x}=\dfrac{a}{3}$ and $\overline{y}=\dfrac{a}{3}$