from math import sqrt

vectors = {"cat": [1.0, 0.2], "dog": [0.9, 0.3], "car": [0.1, 1.0]}

def cosine(a, b):
    dot = sum(x*y for x, y in zip(a, b))
    return dot / (sqrt(sum(x*x for x in a)) *
                  sqrt(sum(y*y for y in b)))

for word in ("dog", "car"):
    print(word, round(cosine(vectors["cat"], vectors[word]), 3))