Symbols in Geometry
Common Symbols Used in Geometry
Symbols save time and space when writing. Here are the most common geometrical symbols:
Symbol | Meaning | Example | In Words |
---|---|---|---|
Triangle | ABC has 3 equal sides | Triangle ABC has three equal sides | |
Angle | ABC is 45° | The angle formed by ABC is 45 degrees. | |
Perpendicular | ABCD | The line AB is perpendicular to line CD | |
Parallel | EFGH | The line EF is parallel to line GH | |
Degrees | 360° makes a full circle | ||
Right Angle (90°) | is 90° | A right angle is 90 degrees | |
Line Segment "AB" | AB | The line between A and B | |
Line "AB" | The infinite line that includes A and B | ||
Ray "AB" | The line that starts at A, goes through B and continues on | ||
Congruent (same shape and size) | ABC DEF |
Triangle ABC is congruent to triangle DEF | |
Similar (same shape, different size) | DEFMNO | Triangle DEF is similar to triangle MNO | |
Therefore | a=b b=a | a equals b, therefore b equals a |
Example:
When someone writes: In ABC, BAC is
They are really saying: "In triangle ABC, the angle BAC is a right angle"
Naming Angles
For angles the central letter is where the angle is.
Example:
when we write "ABC is 45°", the point "B" is where the angle is.