import math

def deg(rad: float) -> float:
    return (rad * (180.0 / math.pi)) - 90

def rad(deg: float) -> float:
    return (deg + 90) * (math.pi / 180.0)

def knots(ms: float) -> float:
    return ms * 1.944

def kelvin(c: float) -> float:
    return 273.15 + c

def celsius(k: float) -> float:
    return k - 273.15