The pangaea theory supports the theory of plate tectonics because

The theory is based on the idea that all the present continents were one super-continent.

Explanation:

Pangaea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras, and it began to break apart about 175 million years ago. The theory supports the idea that all the present continents were one super-continent. For an unknown reason, it got separated and created separate smaller continents, which are the ones that exist now.