Look at the picture.
Definitions:

We have:
and Quadrant II (x < 0, y > 0)
Therefore x=-3 and y = 2. Calculate r:

Substitute to the formula of cosine:

Answer: a.
Answer:
Can you type out the question? it is hard to read and the angle makes it harder
Step-by-step explanation:
Answer:
Surface Area > 1500, since its cube
Answer:
the demonstrated property is associative law any vector can be added in any form
Use photomath it's an app used for mathematic problems but not word problems