For the Young's Double slit Experiment, I'm just wondering when it comes to finding the distance between the adjacent fringes (shown on the screen), why can't we just measure directly the distance between the adjacent fringes instead of having to measure the distance between 5 fringes and dividing by 5. Can there be inconsistencies when it comes to measuring directly the distance between adjacent fringes? I'm really confused about this. HELP!!