Definition
Octagon
An octagon is a flat, closed shape made from exactly eight straight sides.
Continue from this idea into connected AXIO math.
What it means
Trace the edge and count each straight piece once. If the path closes after side 8, the shape is an octagon. It can be wide, tall, tilted, or uneven; eight sides is the deciding property.
Remember it
Octa means eight: walk around the border and stop when you count 8 sides.
Example
A designer draws a closed shape with side lengths 3, 2, 4, 2, 3, 4, 2, and 2 cm. There are eight straight sides, so the shape is an octagon even though the sides are not all equal.
Watch for
A closed shape made from eight curved pieces is not an octagon, because polygon sides are straight.
Common mix-up
A stop-sign outline is a regular octagon, but not every octagon has equal sides or equal angles.
Exact meaning
An octagon is a polygon with eight straight sides and eight vertices. Its side lengths and angles may vary, so an octagon does not have to be regular.