What is the primary difference between Audi A3 and A4?

I am considering purchasing an Audi sedan and am wondering about the differences between the A3 and A4 models. Can anyone provide a more technical explanation of the distinctions between the two?

The main difference between the Audi A3 and A4 lies in their size and performance. While the A4 is a larger and more powerful vehicle, the A3 offers better fuel efficiency and a more nimble driving experience.

One of the key differences between the Audi A3 and A4 is their engine options. The A3 offers a range of smaller turbocharged engines, while the A4 has a more powerful V6 engine option.

In terms of interior features, the Audi A4 offers more luxury and advanced technology compared to the A3. This includes features like Audi's virtual cockpit display and a larger infotainment screen.