Hi I watched an interesting video about Mathematical Trading Strategy and I have a question..

lets say I have two points in the chart:

first point is the price entry (where I open a long position for example)

second point would be a TP, SL or another important price for my trading

IF I want to open a second position..exactly in the middle of the two points in the chart how can I calculate that point as fast as possible? or if I want to calculate another point at 75% between those two points?

Its a Mathematical Trading Strategy so I need that this new position is opened exactly in the middle of those two points  in this example