Why does the Audi 80 have a 5-cylinder engine?

I heard that the Audi 80 has a unique 5-cylinder engine, why did they choose this specific configuration and what benefits does it offer?

The Audi 80's 5-cylinder engine was chosen because it offered a great balance between performance and fuel efficiency. Having an odd number of cylinders means less engine vibrations and smoother running, while the additional cylinder provides more power compared to a 4-cylinder engine.