The required code in python 3.6



import math
#calculates the dotproduct of two vectors
def dotproduct(v1,v2):
   sum = 0;
   for i,j in zip(v1,v2):
       sum = sum + (i*j)
   return sum

#calculates magnitude of a vector
def magnitude(v):
   return math.sqrt(dotproduct(v,v))

#returns angle between two vector in degrees
def angleBetweenVector(v1,v2):
   angleInRadians = math.acos(dotproduct(v1,v2)/   (magnitude(v1)*magnitude(v2)))
   angleInDegrees = angleInRadians *180 / math.pi
   return angleInDegrees

#take user inputs
arr =    input("3D coordinates of obeserver: ")
vo = [int(num) for num in arr.split()]
arr =    input("3D coordinates of point 1 : ")
v1 = [int(num) for num in arr.split()]
arr =    input("3D coordinates of point 2 : ")
v2 = [int(num) for num in arr.split()]
#calculate displacement vector
vo1 = [i-j for i,j in zip(v1,vo)]
vo2 = [i-j for i,j in zip(v2,vo)]
#output
print("The magnitude of displacement vector(point 1 - observer) is : " + str(magnitude(vo1)))
print("The magnitude of displacement vector(point 2 - observer) is : " + str(magnitude(vo2)))
print("The dot product between vectors is : " + str(dotproduct(vo1,vo2)))
print("The angle between vectors in degrees is : " + str(angleBetweenVector(vo1,vo2)))

for indentation refer screenshot attached
https://media.cheggcdn.com/media%2Fd38%2Fd386a700-5ad6-4b73-8f05-656eb0d80d93%2Fphpicxyrw.png

https://media.cheggcdn.com/media%2F4b2%2F4b291b61-d360-4ab5-b240-f58a33c9a727%2Fphp5Xm9k8.png