Tessellation Math Example 1

Follow the full solution, then compare it with the other examples linked below.

Example 1

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Explain why regular hexagons tessellate the plane but regular pentagons do not.

Solution

  1. 1
    For a regular polygon to tessellate alone, its interior angle must divide 360°360° evenly.
  2. 2
    Interior angle of a regular hexagon: (62)×180°6=120°\dfrac{(6-2)\times180°}{6} = 120°. And 360°÷120°=3360° \div 120° = 3 (whole number). So exactly 33 hexagons meet at each vertex. ✓
  3. 3
    Interior angle of a regular pentagon: (52)×180°5=108°\dfrac{(5-2)\times180°}{5} = 108°. And 360°÷108°=3.3360° \div 108° = 3.\overline{3} (not a whole number). ✗
  4. 4
    Since 3.33.\overline{3} pentagons cannot fit exactly around a vertex, regular pentagons do not tessellate.

Answer

Regular hexagons tessellate (interior angle 120°120° divides 360°360° exactly); regular pentagons do not (interior angle 108°108° does not).
The vertex condition for a regular polygon tessellation requires that the interior angle divides 360°360° evenly. Only equilateral triangles (60°60°), squares (90°90°), and regular hexagons (120°120°) satisfy this among all regular polygons.

About Tessellation

A tessellation is a pattern that covers an infinite plane with repeated geometric shapes, leaving no gaps and having no overlaps.

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