Often when price moves away from a level of resistance and then...

Often when price moves away from a level of resistance and then returns to break above or below that level of resistance it will move an equal distance past the resistance level in the opposite direction. In my chart above price rose to $29.48 above a level of resistance/support around $23.79 (a difference of $5.69) take that amount away from $23.79 and you get $18.10. The calculation and line drawing is done with price extensions in my charting software. This explanation is a bit simplistic because there are other aspects of the pattern I look for - but its the basic way it works. Like all things in T/A it doesn't work every time but it works more often than it doesn't and the targeting is usually on the money.