Step-by-step explanation
a vectors makes a rigth angle to the x-positve axis , so
so, the x coordinate is adjacent side and the y-coordinate becomes into the opposite side, then we can use a trigonometric function that relates those values,it is

hence
Step 1
a)
let

replace and solve for the angle

so,
a)Blank1: 30.964
Step 2
b)
let

replace and solve for the angle

so,
b)Blank2:128.660
Step 3
c)

replace and solve for the angle

so,
c)Blank3:-45 °
Step 4
d)

replace and solve for the angle

so,
direction

graph
d)Blank4: 194.036
I hope this helps you