Question

how many degrees did the arrow turn?
(there is a coordinate system with n, s, e, w and a right - angled mark at the intersection point v, and an arrow from w to e and a purple right - angled sector at the upper right of v)

Explanation:

Step1: Identify angle type

The shaded angle is a right angle, which is defined as $90^\circ$.

Step2: Confirm turn measure

The arrow turns across this right angle, so the turn degree equals the angle measure.

Answer:

90