def calculate_junction_temperature(
    temperature_case: float,
    power_operating: float,
    theta_jc: float,
) -> float:
    """Calculate the junction temperature (Tj).

    :param temperature_case: the temperature of the IC case in C.
    :param power_operating: the operating power if the IC in W.
    :param theta_jc: the junction-case thermal resistance in C / W.
    :return: _t_j; the calculate junction temperature in C.
    :rtype: float
    """
    return temperature_case + power_operating * theta_jc