20 Questions · All Topics · ACT-Style Difficulty
| Quadratic Formula | x = (−b ± √(b²−4ac)) / 2a |
| Vertex Form | y = a(x−h)² + k; vertex = (h, k) |
| Sum of roots | r₁ + r₂ = −b/a |
| Product of roots | r₁ · r₂ = c/a |
| Discriminant | b²−4ac: >0 two real, =0 one real, <0 no real |
| Circle area | A = πr² |
| Arc length | L = (θ/360°) × 2πr |
| Sector area | A = (θ/360°) × πr² |
| 30-60-90 triangle | sides: x, x√3, 2x |
| 45-45-90 triangle | sides: x, x, x√2 |
| Distance formula | d = √((x₂−x₁)² + (y₂−y₁)²) |
| Midpoint | M = ((x₁+x₂)/2, (y₁+y₂)/2) |
| Slope | m = (y₂−y₁)/(x₂−x₁) |
| sin²θ + cos²θ | = 1 |
| tan θ | = sin θ / cos θ |
| Law of Sines | a/sin A = b/sin B = c/sin C |
| Law of Cosines | c² = a² + b² − 2ab·cos C |
| sin 30° = cos 60° | = 1/2 |
| sin 45° = cos 45° | = √2/2 |
| sin 60° = cos 30° | = √3/2 |