1. Analytical Fundamentals
Distance = √[(x₂ - x₁)² + (y₂ - y₁)²]
Midpoint = [(x₁ + x₂)/2, (y₁ + y₂)/2]
Slope (m) = (y₂ - y₁) / (x₂ - x₁)
Area of Δ = 0.5 |x₁(y₂ - y₃) + x₂(y₃ - y₁) + x₃(y₁ - y₂)|
Internal Division = [(mx₂ + nx₁)/(m+n), (my₂ + ny₁)/(m+n)]
External Division = [(mx₂ - nx₁)/(m-n), (my₂ - ny₁)/(m-n)]