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Geometry › Symbols
Geometric symbols
A geometer's shorthand — once you know the marks, every diagram reads faster.
Symbol matching game
Drag each symbol onto its name. 0/8 matched.
Symbols deck
≅
π
∠
~
°
∥
⊥
△
Drop on the matching name
Congruent
?
△ABC ≅ △DEF
Similar
?
△ABC ~ △DEF
Degrees
?
90°
Parallel
?
AB ∥ CD
Pi
?
π ≈ 3.14159
Perpendicular
?
AB ⊥ CD
Angle
?
∠ABC = 60°
Triangle
?
△ABC
Reading a labelled diagram
When you see hash marks on two sides of a triangle, those sides are the same length. When you see a small square in a corner, that corner is a right angle. Arrows in the middle of two lines mean the lines are parallel.
Naming things
- Points — single capital letter: A, B, C.
- Lines / segments / rays — by their two endpoints: AB.
- Angles — by three points (vertex in the middle): ∠ABC.
- Triangles — by their three vertices: △ABC.
Why notation matters
One labelled diagram can carry the equivalent of a paragraph of words. The symbols aren't decoration — they're how geometers compress logical relationships into a picture you can scan in a second.