For the first part, the answer is choice B) 360. This applies to any polygon and it doesn't have to be an octagon. The sum of the exterior angles of any polygon is always 360 degrees. This is something you should memorize or have on a reference sheet.
For the second part, the answer is choice C) 142 degrees. We have a parallelogram (specifically a rhombus but that doesn't matter) so the adjacent angles are supplementary. This means they add to 180 degrees. Solving x+38 = 180 leads to x = 142
<h2>
Answer:</h2>

<h2>
Step-by-step explanation:</h2>
In this problem we have two vectors:

So we need to find two things:

and:

FIRST:
In this case we have the multiplication of vectors by scalars. A scalar is a simple number, so:

SECOND:
If we name:

Then,
is the magnitude of the vector
. Therefore:

Answer:
(-6, -5)
Step-by-step explanation:
Reflection across the y-axis leaves the point on the same horizontal line, but with the sign of its x-coordinate changed.
(x, y) ⇒ (-x, y) . . . . . reflection across the y-axis
(6, -5) ⇒ (-6, -5)
The image point is (-6, -5).
Answer:
nothing
Step-by-step explanation:
nothing
Answer:
-1 1/2
Step-by-step explanation: