1. Define a coordinate system. I suggest the origin to be the midpoint of the horizontal distance.

2. Then the general equation of the parabola is

p(x) = a x^2+32

3. You know the coordinates of V(0, 32) and B(42, 0). Plug in the coordinates of B into the equation of the parabola:

0 = a*(42)² + 32 ==> a = - 8/441

The complete equation is : p(x) = -8/441 * x^2 + 32

4. To use 6 vertical beams you have to divide the horizontal span into7equal distances (why?). Make a table and calculate p(-30), p(-18), ... p(30). For symmetry reasons you only have to calculate 3 values.