How were the greeks able to defeat the persians?

In general, it appears that the Greeks were able to defeat the Persians because of their superior battle tactics.

For example:

At Marathon, the Persian attack on the weakened Greek center allowed the strengthened Greek flanks to attack and essentially encircle the Persians.

The greeks were able to defeat the Persians because of their superior battle tactics. Hope this helped!

classical republicanism, also known as civic humanism, is a form of republicanism  developed in the renaissance inspired by the governmental forms and writings of  classical  antiquity, especially such  classical  writers as aristotle, polybius, and cicero.