Continuing with the theme of Physical Economics presented in previous papers by the same author, we develop a solution from the stiffness equation from Structural Engineering that allows us to calculate the GDP growth for a broad economy. It is important because this solution can be programmed into computer language to solve for the critical variables that need to be determined to manage the economy. Knowledge of Astrotheology Mathematics is helpful in understanding where some the variable come from and why the golden mean parabola is particularly important.