Which pairs of angles in the figure below are verticals angles ? check all that apply.
a. ksw and nst
b. tsn and isw
c. wsi and isk
d. isn and tsw

mark two options:

B. TSN and ISW

D. ISN and TSW

Explanation:

Recall the definition of vertical angles as: those angles opposed by the vertex, and which are the result of two lines that intersect.

In the figure given there are two pairs such angles, one pair I depicted in red, and the other one in blue, while the intersecting lines are shown in green. Notice that when two lines intersect, there are always two pairs of vertical angles being generated.

Therefore, according to the notation given, two boxes need to be checked in the set of options:

1) the one corresponding to : TSN and ISW (blue ones in the attached image)

and

2) the one corresponding to ISN and TSW (red ones in the attached image)