This problem describes a volume whose base is bounded by the equation $y = 9 - \frac{9}{49}x^2$ and $y = 0$, with cross sections perpendicular to the x-axis that are triangles whose height and base are equal.

Steps to solve:

1. Identify the region of the base: The equation $y = 9 - \frac{9}{49}x^2$ is a parabola, symmetric about the y-axis. The base of the volume is bounded by this curve and the x-axis (i.e., $y = 0$).

2. Limits of integration: Find where the parabola intersects the x-axis by setting $y = 0$: $9 - \frac{9}{49}x^2 = 0$ Solving this gives: $\frac{9}{49}x^2 = 9 \quad \Rightarrow \quad x^2 = 49 \quad \Rightarrow \quad x = \pm 7$ So, the region is from $x = -7$ to $x = 7$.

3. Area of cross-sections: Every cross-section is an equilateral triangle. The side of the triangle is given by the distance from the x-axis to the curve, which is $y = 9 - \frac{9}{49}x^2$. The area $A$ of an equilateral triangle with side $s$ is: $A = \frac{\sqrt{3}}{4}s^2$ Since the height and base of the triangle are equal, the side $s$ of the triangle is the same as the value of $y$ (the height from the x-axis to the curve), i.e., $s = y = 9 - \frac{9}{49}x^2$.

   Thus, the area of each triangular cross-section is: $A(x) = \frac{\sqrt{3}}{4}\left(9 - \frac{9}{49}x^2\right)^2$

4. Volume integral: The volume is the integral of the area of the cross-sections along the x-axis from $x = -7$ to $x = 7$: $V = \int_{-7}^{7} A(x) \, dx = \int_{-7}^{7} \frac{\sqrt{3}}{4}\left(9 - \frac{9}{49}x^2\right)^2 dx$

5. Simplify and compute: You would now expand and evaluate this integral to find the volume.

Let me know if you would like me to calculate this for you! Would you also like further details or have any other questions?

Here are five related questions you could explore:

1. How do you compute the volume of a solid with different cross-sectional shapes?
2. What is the formula for the area of a triangle in terms of its sides?
3. How can we visualize solids generated by cross-sections?
4. What are other types of common cross-sectional solids in calculus problems?
5. How does changing the curve defining the base affect the volume of the solid?

Tip: Whenever working with volumes involving cross-sections, always check if the cross-sections vary with the axis you're integrating over!