Mentor note: Thread moved from a homework section. I don't know if this is the right forum, but this isn't really a homework question that I have to solve, I am just trying to get better with vectors/trig and I looked at this for basic examples. I am okay with finding x and y components, but I am unsure why the woman in the video used cos-1 in the first example to find an angle but not in the second. She breaks the second example down into one nice and neat right triangle and has all the values for all three sides in meters but doesn't use cos-1 in the second example as she did in the first, despite having all values for each side??? Can anyone clarify for me?