Adjust the octagon below by dragging any orange dot. By clicking on the top left command line,
you can switch it between a
Because an octagon has an even number of sides, in a
regular octagon, opposite sides are
Properties of regular octagons
Like any regular polygon, to find the interior angle we use the formula
(180n–360)/n . For an octagon, n=8.
See Interior Angles of a Polygon
To find the exterior angle of a regular octagon, we use the fact that the exterior angle
with the interior angle, so in general it is given by the formula
See Exterior Angles of a Polygon
Houses and rooms are sometimes built in an octagonal shape (pronounced: "ock-TAG-on-all"), perhaps because they
feel somewhat like a circular space but are made of straight wall sections which are easier to build.
While no longer so popular, there are examples that are being preserved as historic buildings.
The one on the right is the
Loren Andrus Octagon House in Washington, Michigan USA, built in 1860.
Because they are based on a regular octagon, opposite walls are parallel and the rooms have a pleasing symmetry.