Suppose $\displaystyle{ f(x) = \frac{x^2}{9} }$.

1. The rectangles in the graph on the left illustrate a left endpoint Riemann sum for $f(x)$ on the interval $3 \leq x \leq 5$. The value of this left endpoint Riemann sum is and it is an ? overestimate of equal to underestimate of there is ambiguity the area of the region enclosed by $y = f(x)$, the $x$-axis, and the vertical lines $x = 3$ and $x = 5$.
2. The rectangles in the graph on the right illustrate a right endpoint Riemann sum for $f(x)$ on the interval $3 \leq x \leq 5$. The value of this right endpoint Riemann sum is and it is an ? overestimate of equal to underestimate of there is ambiguity the area of the region enclosed by $y = f(x)$, the $x$-axis, and the vertical lines $x = 3$ and $x = 5$.