Hey there! :)
Answer:
(3.5, -1).
Step-by-step explanation:
Use the midpoint formula to solve this problem:

Plug in the coordinates given:

Simplify:

Therefore, the coordinates of the mid-point are:
(3.5, -1).
The question ask to determine what is a regular polygon that contains an interior angle of 9000 degree, base on my research, according to the geometrical research, I would say that the said polygon is a 52 sided convex polygon. I hope this would help
<span>8d – 4d – 6d – 8 = 2d
</span><span>8d – 4d – 6d – 2d = 8
-4d = 8
d = -2</span>
B because it is the midpoint for segment shown above