Manually raising two error types with a function that computes sqfeet to sqmeters

[sean1]

I keep getting TypeError: unsupported operand type(s) for /: 'str' and 'float'. How do I manage to raise the errors successfully as well as removing this reoccurring TypeError? Please help!!! Thank you in advance!!

def sqfeet_to_sqmeters(a_value):
    answer_in_sqmeters = a_value / 10.764 ** 2
    try:
        if type(a_value) == float:
            return answer_in_sqmeters
    except:
        try:
            if type(a_value) != float:
                raise TypeError(ERROR_NAN)
        except TypeError:
            if a_value < 0:
                raise ValueError(ERROR_NEGATIVE)
a_value = input("Enter area in square feet: ")
print(sqfeet_to_sqmeters(a_value))