How to draw triangle CSS

Question

Hello everybody, help please with next : i want draw triangle via Css, thanks

Answer 1

Daniil Timonov
https://code.sololearn.com/WaDy6Xfuv4MD/?ref=app

Answer 2

https://css-tricks.com/working-with-shapes-in-web-design/

Answer 3

Сергей спасибо