← Back to Module 1

Module 1: Quick Reference Card

Angles and Their Measure

Angle Types

Acute: 0° < θ < 90°

Right: θ = 90°

Obtuse: 90° < θ < 180°

Straight: θ = 180°

Reflex: 180° < θ < 360°

Key Relationships

Complement: 90° − θ
Supplement: 180° − θ
Coterminal: θ ± 360° or θ ± 2π

Degree-Radian Conversions

180° = π radians  |  Deg → Rad: × π/180  |  Rad → Deg: × 180/π
0°30°45°60°90°120°135°150°180°
0π/6π/4π/3π/22π/33π/45π/6π
210°225°240°270°300°315°330°360°
7π/65π/44π/33π/25π/37π/411π/62π

Arc Length & Sector Area

s = rθ
A = (1/2)r²θ

θ must be in radians!

Angular & Linear Speed

ω = θ/t
v = s/t = rω
Gears: r₁ω₁ = r₂ω₂

1 rev = 2π rad