Ok, this is a super easy way to create a triangle in Illustrator. And it does not involve the "wonderful and awesome" Pen Tool.
I post this because I have seen many, many people over the years trying to draw and equilateral triangle with every tool and method, all of which were not easy. And people struggled to make things perfect... or close enough.
Start by selecting the Polygon Tool nest in the shape tools in the tool bar. By default it draws 6 sides, or it uses the last preset used.
If you hold SHIFT, it will keep the bottom side perfectly horizontal.
Hold the mouse down while drawing and don't let go or else you will have to start over!
With the mouse held down while drawing, use the DOWN ARROW on your keyboard to reduce the number of side to 3. Hold the SHIFT to keep the bottom side horizontal.
Another method is to take the Polygon Tool and just CLICK on the document, don't draw with it.
Clicking will open up a dialog box and you can set the number of sides and the Radius.
Radius is the measurement from the center to an outside point.
Once you set this, it will become your new preset for the Polygon tool while you have the document open and you can just draw yourself hundreds of triangles if you want.
Thanks for viewing and please pass this along!