How to construct (draw) a 45 degree angle with compass and straightedge or ruler - Math Open Reference
![How to construct (draw) a 45 degree angle with compass and straightedge or ruler - Math Open Reference](https://www.mathopenref.com/images/constructions/constangle45/proof.png)
This page shows how to construct (draw) a 45 degree angle with compass and straightedge or ruler. It works by constructing an isosceles right triangle, which has interior angles of 45, 45 and 90 degrees. We use one of those 45 degree angles to get the result we need. See the proof below for more details. A Euclidean construction.
![](https://upload.wikimedia.org/wikipedia/commons/9/9f/R%C3%A9gua_e_compasso.jpg)
Straightedge and compass construction - Wikipedia
Constructing A 45 Degree Angle, PDF, Elementary Mathematics
How to construct a 45 degree angle - Quora
![](https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Basic_constructions_animation_with_text.gif/800px-Basic_constructions_animation_with_text.gif)
Straightedge and compass construction - Wikipedia
![](https://i.stack.imgur.com/0p3bm.png)
geometry - How to give my students a straightedge instead of a ruler - Mathematics Educators Stack Exchange
![](https://www.wikihow.com/images/thumb/0/03/Construct-a-30-Degrees-Angle-Using-Compass-and-Straightedge-Step-1.jpg/v4-460px-Construct-a-30-Degrees-Angle-Using-Compass-and-Straightedge-Step-1.jpg.webp)
How to Construct a 30 Degrees Angle Using Compass and Straightedge
How can we divide a right angle into five equal parts with ruler and compass? - Quora
Constructing 30deg Angle, PDF, Triangle
![](https://upload.wikimedia.org/wikipedia/commons/thumb/0/07/SqrtGeom.gif/252px-SqrtGeom.gif)
Straightedge and compass construction - Wikipedia