def areacirculo(radio):
  areacirculo=M. pi*M. pow(radio,2)
  print areacirculo
def areatriangulo(b,h):
 areatriangulo=b*h/2
 print areatriangulo
def areacuadrado(l):
 areacuadrado=M. pow(l,2)
 print areacuadrado
def areaoctagono(apotema,lado):
  areaoctagono=4*lado*apotema
  print areaoctagono
  
