Degree symbol (°) represents degrees of arc, hours, temperature and alcohol proof. Term "degree" comes from Latin gradus, meaning any stage in graded system. Modern notation appeared in print in 1570s, popularized by Brahe and Kepler. Temperature scales introduced in 18th century without degree symbols
Trigonometric functions relate sides of right triangles to angles. Right triangle sides include adjacent, opposite, and hypotenuse. Trigonometric functions can be evaluated for any acute angle
Trigonometric functions model various phenomena including sound waves and pendulum motion. Angle measures can be converted between degrees and radians. Radians are more natural due to direct connection to unit circle
Hexagon is a 2D figure with six straight edges. Named after "hex" (six) and "gonia" (corners). Can be regular or irregular based on side lengths
Sin 1 is a trigonometric function for 1° with value 0.01745. Can be expressed in degrees or radians with same value. Based on right triangle with opposite/hypotenuse ratio
1 gradian equals 0.9 degrees. Conversion formula: degrees = gradians × 0.9