Distance Between Two Parallel Lines

To find the distance between two parallel lines, $ax+by+c_1=0$ and $ax+by+c_2=0$, use the formula:

Distance = $\frac{|c_1 - c_2|}{\sqrt{a^2 + b^2}}$

This formula finds the difference in the constant terms and divides by the magnitude of the normal vector. The equations must have the same coefficients for x and y. Again, $a$ and $b$ often form a Pythagorean triple.