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A tessellation is a pattern created with identical shapes which fit together with no gaps or overlaps.

Examples of tessellations
Image caption,
Examples of tessellations

Tessellations in nature

A pineapple, a turtle, a honeycomb and Giant's Causeway.
Image caption,
Clockwise from top left: a pineapple, a turtle, Giant's Causeway, a honeycomb.

Tessellations in nature have inspired tessellations in building, construction.

Image caption,
Building and construction inspired by tessellations.

Tessellating triangles

Since the sum of the angles in a triangle is \(180^\circ\), three identical triangles can be placed along a straight line.

Three identical triangles in a row.
Figure caption,
Three identical triangles in a row.

By copying and rotating this pattern, six identical triangles can be placed together at a point leaving no gaps.

Six identical triangles placed together at a point leaving no gaps.

This pattern can be repeated leaving no gaps.

This is a tessellating pattern.

A tessellating pattern.

Key point

All triangles tessellate.

Example

Prove that this triangle tessellates?

Triangle with internal angles of 68, 75 and 37 degrees

Answer

Three identical triangles will fit together on a straight line since:

\(37^\circ + 68^\circ + 75^\circ = 180^\circ \)

Six identical triangles will fit together at a point since:

\(37^\circ + 68^\circ + 75^\circ + 37^\circ + 68^\circ + 75^\circ = 360^\circ \)

Therefore, the triangle tessellates.

Three triangles joined together

Tessellating regular polygons

Regular polygons will tessellate if the size of the angle is a factor of \(360^\circ\).

Equilateral triangles have angles of \(60^\circ\).

\(360^\circ \div 60^\circ = 6\)

6 equilateral triangles will fit together at a point with no gaps or overlaps.

Equilateral triangles tessellate.

Six identical triangles fit together.

Squares have angles of \(90^\circ\).

Small square

\(360^\circ \div 90^\circ = 4\)

4 squares will fit together at a point with no gaps or overlaps.

Squares tessellate.

Large square.

Example

Do regular pentagons tessellate?

Regular pentagons have angles \(108^\circ\).

Regular pentagon.

\(360^\circ \div 108^\circ = 3.333333鈥)

3 pentagons leave a gap.

Three regular pentagons joined together.

4 will overlap.

Regular pentagons do not tessellate.

Four pentagons joined and overlapping

Question

Do regular hexagons tessellate?

Regular hexagon

Key point

Polygons with angles bigger than \(120^\circ\) will NOT tessellate.

More on 2D shapes

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