$(1$ point$)$ The rectangles in the graph below illustrate a left endpoint Riemann sum for $f(x)=\frac{x^2}{11}$ on the interval $[3,7].$

The value of this left endpoint Riemann sum is $,$ and this Riemann sum is $$ an underestimate of the area of the region enclosed by $y=f(x),$ the x $-$axis, and the vertical lines $x=3$ and $x=7.$