Being well versed in the math class helps the most:

# Enter your code here. Read input from STDIN. Print output to STDOUT
import math

AB = int(input())
BC = int(input())



AC = math.sqrt((AB ** 2) + (BC ** 2))
print(f"{round(math.degrees(math.acos(BC/AC)))}\N{DEGREE SIGN}")

import math

ab = int(input()) bc = int(input())

angle_rad = math.atan2(ab, bc) angle_deg = math.degrees(angle_rad)

print(round(angle_deg)) out is 45 just number but need 45° how

Here is HackerRank Find Angle MBC solution in Python - https://programmingoneonone.com/hackerrank-find-angle-mbc-solution-in-python.html

import math ab= float(input()) bc= float(input()) angle_mbc= math.degrees(math.atan(ab/bc)) print(str(round(angle_mbc)) + chr(176))

Law of Cosines

import math x = int(input()) y = int(input()) a = math.sqrt((x*x)+(y*y)) b = a/2

z = math.acos((y*y)/(2*y*b)) k = math.degrees(z) print(f'{int(round(k))}\u00B0')