When appending a tuple to a list, I can append (a + b + c) or (a, b + c) or (a + b, c) but appending (a, b ,c) causes the program to refuse to run

Question

Here\'s the code

def check_right_angle(a, b, c):
    if a**2 + b**2 == c**2:
        return True
    return False

def mn_to_abc(m, n):
    return m**2 - n**2