Your text should go through the derivation of the period of the pendulum,so we will not replicate it here. However, you should note that the form isof a general nature; 2 multiplied by a ratio under a square root, of whichis a dynamic variable over a measure of the acceleration of the system. Inthe case of the pendulum, the dynamic variable, or the thing that changes,is the length, and the acceleration is that of gravity.