freeCodeCamp/guide/english/mathematics/supplementary-angles/index.md

---
title: Supplementary Angles
---
## Supplementary Angles
Two angles which sum up to 180° are called supplementary angles.

![Image showing two angles, one with 120 degrees and the other with 60 degrees](https://raw.githubusercontent.com/pranabendra/articles/master/Supplementary-angles/images/sup1.png)

Supplementary angles don't have to be next to each other, just so long as the total is 180°. Here's an example:

![Parallel lines a and b with line t through them, creating 8 angles](https://raw.githubusercontent.com/pranabendra/articles/master/Supplementary-angles/images/sup2.png)

As `a` is parallel to `b`, <b>angles</b> "`3`" and "`6`" sum up to 180&deg;. Hence, they are supplementary angles.

### More Information:
- Supplementary Angles article: <a href='https://www.varsitytutors.com/hotmath/hotmath_help/topics/supplementary-angles' target='_blank' rel='nofollow'>Varsity Tutors</a>