If I did not know that the coefficient $K$ of the frequency of the pendulum; $\frac{1}{t} = K*(g/L)^{\frac{1}{2}}$ is $\frac{\pi}{2}$, how would I go about finding it? Is there any textbook that I could take a look at? I found some equations through unconventional means with similar structures, but my numbers do not agree with the answers on textbooks. I just need some idea.
Thank you for your time.