# Geometry for Elementary School/Conventions

 Geometry for Elementary School Glossary Conventions

This appendix summarises the conventions used in this book. There is also a British-American English differences table provided.

## Language

All the language in this book uses simple British English. Alternative names in American English are listed below.

British English American English Other names
Vertically opposite angles Vertical angles /
The right angle-hypotenuse-side congruence theorem (RHS) The hypotenuse-leg congruence theorem (HL) The hypotenuse-leg-right angle theorem (HLR)
Centre Center /
Compass Compass A pair of compasses (British)
Trapezium Trapezoid /
Centimetre / Millimetre / Metre / Kilometre Centimeter / Millimeter / Meter / Kilometre /
Millilitre / Litre Milliliter / Liter /

## Notation

This appendix summarises the notation used in the book. An effort was made to use common conventions in the notation. However, since many conventions exist the reader might see a different notation used in other books.

Point

A point will be named by an uppercase letter in italics, as in the point A. In some equations though, it will look like this: ${\displaystyle A}$.

Line segment

We will use the notation ${\displaystyle {\overline {AB}}}$ for the line segment that starts at A and ends at B. Note that we don't care about the segment direction and therefore ${\displaystyle {\overline {AB}}}$ is similar to ${\displaystyle {\overline {BA}}}$.

Angles

We will use the notation ${\displaystyle \angle {ABC}}$ for the angle going from the point B, the intersection point of the segments ${\displaystyle {\overline {BA}}}$ and ${\displaystyle {\overline {BC}}}$. Sometimes the angle may also be represented by a lowercase letter or even a number, but this is only used in the main text for ease and not in the exercises.

Triangles

A triangle whose vertices are A, B and C will be noted as ${\displaystyle \triangle ABC}$. Note that for the purpose of triangles' congruence, the order of vertices is important and ${\displaystyle \triangle ABC}$ and ${\displaystyle \triangle BCA}$ are not necessarily congruent.

Circles

We use the notation ${\displaystyle \circ A,{\overline {BC}}}$ for the circle whose center is the point A and its radius length equals that of the segment ${\displaystyle {\overline {BC}}}$.

Note that in other sources, a circle is described by any 3 points on its circumference, ABC. The center, radius notation was chosen since it seems to be more suitable for constructions.