This study explores the question of why the fundamental forces in the universe, the fundamental interactions, vary so greatly in strength. The integration of results from the mathematical optimization method of optimal potential towers with physics demonstrates that there is a fundamental relationship between the relative strengths of the interactions, as well as with the number of dimensions in the universe. It allows for the derivation and calculation of the previously unexplained value of the fine-structure constant, which has remained a mystery for a hundred years. Predicted value: 137.035999100.