Assigning float variable value based on yes-no user input

import math

#pie price per square inch (the actual assignment)
def piecost(diameter, price):
    radius = (diameter / 2)
    area = (math.pow(radius, 2)) * math.pi

    return round(price / area, 2)
    #return price / area

#a menu to show the user (I am going to improve on this - right now the user puts in the #diameter size and not a semantic response.
def showprice():
    print("8 inch personal is 6.50")
    print("10 inch small is 10.00")
    print("12 inch medium is 11.50")
    print("14 inch large is 15.50")
    print("16 inch extra large is 18.00")

#the function that adds the 2.00 charge for toppings. Except it doesn't
def toppings(answer):
    baseprice = 0.0
    if answer.lower == 'y':
        baseprice = 2.00

    return baseprice


#price of pizza with or without toppings, as user prefers. Only gives prices without.
def pricecalc(answer, diameter):
    baseprice = toppings(answer)
    price = 0.0
    price = price + baseprice
    if diameter == 8:
        price = price + 6.50
    if diameter == 10:
        price = price +  10.00
    if diameter == 12:
        price = price + 11.50
    if diameter == 14:
        price = price + 15.50
    if diameter == 16:
        price = price + 18.00

    return price

#main and method calls
def main():

    showprice()

    diameter = eval(input("What size pizza pie do you want? "))
    answer = input("Do you want toppings Y/N? ")
    baseprice = toppings(answer)
    pieprice = pricecalc(answer, diameter)
    totalcost = piecost(diameter, pieprice)
    print(str(baseprice))
    print(str(pieprice))
    print(str(totalcost))

    print("Your ", str(diameter), " inch pizza", " is ", str(pieprice), "which is ", str(totalcost), " cents per square inch.")
    print("Goodbye")


main()