Regular Hendecagon (11 sides) — free printable diagram

How many sides does a hendecagon have?

A hendecagon is an eleven-sided shape — a polygon with 11 sides and 11 corners. A regular hendecagon has 11 equal sides and 11 equal angles of ≈147.3°.

Sides

11

Vertices (corners)

11

Interior angles add up to

1,620°

Each interior angle (regular)

≈147.3°

Each exterior angle (regular)

≈32.7°

Diagonals

44

Lines of symmetry (regular)

11

Also called

eleven-sided figure, eleven-sided polygon

• The interior angles of any hendecagon add up to (11 − 2) × 180° = 1,620°.
• A regular hendecagon has every angle the same, so each one measures 1,620° ÷ 11 = about 147.3°.
• A hendecagon has 44 diagonals — 11 × (11 − 3) ÷ 2.