Why do I need to learn html, c++,python, java, ruby?

Answer 1

Well, nobody forces you to learn all of them. It's better to focus on what do you want to achieve with a language. Do you want to make web applications, windows apps, etc.

Answer 2

Не учи вовсе. Зачем тебе это?

Answer 3

because of developing web application.
example Facebook web application, Amazon web application, Google search engine. YouTube application. even everything around with web application.