Learn Italian: L'acrobata è agile, perciò riesce a fare una capriola spettacolare. - The acrobat is agile, therefore he manages to do a spectacular somersault.

Riesce a (from riuscire a) emphasizes successfully completing a task or managing to do something. While sa fare means having the learned skill and può fare means having the permission or opportunity, riesce a fare focuses on the physical ability to successfully pull off this specific spectacular move.

Why is there an a between riesce and fare?

The verb riuscire always requires the preposition a when linking to an action you are managing to do (riuscire a + infinitive). This is different from the other ability verbs potere and sapere, which connect directly to the next verb without a preposition.

The translation says he, but how do we know l'acrobata is masculine?

In this specific Italian sentence, we actually do not know! Acrobata is a noun that ends in -a for both men and women, and the adjective agile ends in -e for both genders. The translation uses he for convenience, but the Italian sentence could perfectly describe a female acrobat.

Can I use quindi instead of perciò in this sentence?

Yes, you can. Perciò means for this reason or therefore. Words like quindi or dunque are synonyms and would work perfectly here to connect the two ideas.