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

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