Reply To: Arched doorway
A visual expansion of Adrian’s answer:
There are different types of arches, but they are always constructed from simple geometrical shapes. Here is an example:
By moving the circles along the X-Axis, the inscribed triangle changes from an equilateral to an isosceles triangle and the arch shape changes with it.
But like already mentioned above, there are many ways to make arches like this in Blender. The reference is the main thing to follow.