Distance Formulas

Distance Between Two Points

$$d = \sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}$$

Distance of a Point from a Line

For a line $Ax + By + C = 0$ and a point $(x_1, y_1)$:

$$d = \frac{|Ax_1 + By_1 + C|}{\sqrt{A^2+B^2}}$$