Geometric calculator in python

#python 3.7.1

print ("-------------------------------WELCOME------------------------------------")
print(" ")

print("  geometric calculator")
print("                   created by  ")
print("                            -_-  Mr. Dark -_-")
print(" ")
ask = input("     <--------------[choose from the below option]----------->\n\n   1:- right angled triangle\n\n   2;- any type of triangle \n\n   3:-area of rectangle\n\n   4:-area of square \n\n   5:- area of parallelogram\n\n   6:- area of circle \n\n    ")
if ask == "1":

  a = float(input("enter the lenght of base\n:-"))
  b = float(input("enter the hight of triangle\n:-"))
  print("area of ∆ =", a*b//2)
 
 
elif ask == "2":
  a = float(input("enter the lenght of first side  :-\n"))
  b = float(input("enter the lenght of second side  :-\n"))
  c = float(input("enter the lenght of third side  :-\n"))
  s = (a+b+c)//2
  p = s-a
  q = s-b
  r = s-c
  print("   ")

  print("semiperimeter of the ∆ =" , s)
  area = (s*p*q*r)**0.5
  print("area of ∆=", area)
 
 
elif ask == "3":
  a = float(input("enter the lenght of rectangle  :-\n"))
  b = float(input("enter the width of rectangle  :-\n"))
  print("area of rectangle=", a*b)
 
 
 
elif ask == "4":
  a = float(input("enter the lenght of side of square :-\n"))
  print("area of square=", a*a)

elif ask == "5":
  a = float(input("enter the lenght of base of parallelogram  :-\n"))
  b = float(input("enter the hight of parallelogram  :-\n"))
  print("area of parallelogram=", a*b)
  print("   ")
 
 
elif ask == "6":
  a = float(input("enter the radius of circle"))
  print("area of circle= ", 3.14*a**a)
else:
  print("you didn't choose correct option \n choose correct option")