A calculator to find the angle between two lines L1 and L2 given by their general equation of the form
a x + b y = c
The formula used to find the acute angle (between 0 and 90°) between two lines L1 and L2 with slopes m1 and m2 is given byθ = |tan -1( (m2 - m1) / (1 + m2 × m1))|
where the slopes m1 and m2 are given by - b / a for each line.α = 180 - θ