› geometry a
solid
shape
with four
flat
,
triangular
surfaces
of
equal
size

(Definition of tetrahedron noun from the Cambridge Academic Content Dictionary
© Cambridge University Press)

You are looking at an entry to do with Geometrical shapes, but you might be interested in these topics from the **Mathematics & arithmetic** topic area:

- Addition, subtraction, multiplication & division
- Averages
- Branches & types of mathematics
- Calculations & calculating
- Fractions
- Geometrical & mathematical instruments
- Geometry: bends, loops & curves
- Geometry: describing angles, lines & orientations
- Geometry: parts of geometrical shapes
- Geometry: properties of circles & curves
- Mathematical symbols
- Numbering & counting
- Numbers generally
- Numbers: cardinal, including nought & zero
- Numbers: groups of things according to number
- Numbers: ordinal
- Numbers: single, double & multiple
- Numerical relationships
- Statistics
- Tables, graphs & diagrams
- Terms for numbers

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