Geometry is a branch of mathematics that deals with the properties of configurations of geometric objects – (straight) lines, circles and points being the most basic.
The area of mathematics that deals with space, lines, shapes and points
Plane Geometry is about flat shapes like triangles, circles, and lines,
Solid Geometry is about solid (3-dimensional) shapes like spheres and cubes.
Let’s explore the typical Geometry symbols used in both basic Geometry and more advanced levels.
Symbol |
Symbol Name |
Meaning / definition |
Example |
\(\angle\) |
measured angle |
ABC = 30º | |
∠ | angle | formed by two rays | ∠ABC = 30º |
∟ | right angle | = 90º | α = 90º |
spherical angle | AOB = 30º | ||
´ | arcminute | 1º = 60´ | α = 60º59′ |
º | degree | 1 turn = 360º | α = 60º |
´´ | arcsecond | 1´ = 60´´ | α = 60º59’59” |
\(\overrightarrow{AB}\) | ray | line that start from point A | |
AB | line segment | line from point A to point B | |
| | perpendicular | perpendicular lines (90º angle) | AC | BC |
≅ | congruent to | equivalence of geometric shapes and size | ∆ABC ≅∆XYZ |
|| | parallel | parallel lines | AB || CD |
Δ | triangle | triangle shape | ΔABC ≅ΔBCD |
~ | similarity | same shapes, not same size | ∆ABC ~∆XYZ |
π | pi constant | π = 3.141592654…
is the ratio between the circumference and diameter of a circle |
c = π·d = 2·π·r |
|x–y| | distance | distance between points x and y | | x–y | = 5 |
grad | grads | grads angle unit | 360º = 400 grad |
rad | radians | radians angle unit | 360º = 2π rad |