To find the volume of a right rectangular pyramid, you can use the formula:
\[ V = \frac{1}{3} \times \text{Base Area} \times \text{Height} \]
First, we need to calculate the base area of the pyramid. The base is a rectangle, so we find the area by multiplying the length and the width.
\[ \text{Base Area} = \text{Length} \times \text{Width} = 26 , \text{m} \times 31 , \text{m} = 806 , \text{m}^2 \]
Next, we can use the height of the pyramid (altitude), which is 35 m, to calculate the volume.
\[ V = \frac{1}{3} \times 806 , \text{m}^2 \times 35 , \text{m} \]
Calculating this, we have:
\[ V = \frac{1}{3} \times 806 \times 35 = \frac{28,210}{3} \approx 9,403.33 , \text{m}^3 \]
Thus, the volume of the pyramid is approximately:
\[ \boxed{9,403.33 , \text{m}^3} \]