Apply the cosine double angle identity to get:
Cos 2PI/3
I believe that would be the last choice, because it is not impossible that someone without contacts or glasses would be chosen. And it is a fairly similar chance that someone with glasses or with contacts will be chosen. Hope this helps! :)
The paper clip's length, as shown in the picture, is closest to C. 2 inches.
I hope this helps :)
The dot product will have you multiply the corresponding coordinates and add up the products
v dot w = (6*(-7)) + (7*5) + (-3*2)
v dot w = -42 + 35 - 6
v dot w = -7 - 6
v dot w = -13
Answer: -13
