Given:
Planes X and Y are perpendicular to each other
Points A, E, F, and G are points only in plane X
Points R and S are points in both planes X and Y
Lines EA and FG are parallel
The lines which could be perpendicular to RS are EA and FG.
Answer:

Step-by-step explanation:
The reference angle is the angle that the given angle makes with the x-axis.
For an ordered pair to share the same reference angle, the x and y coordinates must be the same or a factor of each other.
From the given options:

We observe that only the pair in option C has the same x and y coordinate with the second set of points being a negative factor of the first term. Therefore, they have the same reference angle.
Answer: The answer is 1400000000
Step-by-step explanation:
Acute since right triangles have a 90 degree angle and obtuse triangles have angles in between 90 and 180