A hexagon is a geometric shape with with 6 straight sides. Hex is a Greek prefix which means ‘six.’ A popular shape used in Paper Piecing, the regular hexagon has six sides that all have the same measurement. An interesting fact about the regular hexagon is that it is convex, meaning that the points of the hexagon all point outward. All of the angles of a regular hexagon are congruent and measure 120 degrees. This means the angles of a regular hexagon add up to 720 degrees, or 6 times 120.(Contrast this to a circle, whose inner angles add up to 360 degrees.)
When sizing and measuring hexagons, quilters refer to the length of the sides of the hexagon. Note that this measurement is smaller than the diameter of the shape.