CHARACTERS in geometry and trigonometry

CHARACTERS in geometry and trigonometry.

|| the character of parallelism

Δ triangle

□ square

▭ rectangle

⊙ circle

∠ equiangular, or similar

∠ equilateral

∠ an angle

∠ right angle

∠ perpendicular

° denotes a degree; thus 45° implies 45 degrees, a minute; thus, 50°, is 50 minutes.

′, ″, ‴, ‵, denote seconds, thirds, and fourths: and the same characters are used where the progressions are by tens, as it is here by sixties.