from math import pi

print('radius   area')
for r in range(1,10):
    pi = 3.14
    area = pi*r**2
    print('{:4} {:8.f2}'.format(r, area))

radius   area

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-1-b95c2a79a27e> in <module>()
      5     pi = 3.14
      6     area = pi*r**2
----> 7     print('{:4} {:8.f2}'.format(r, area))

ValueError: Format specifier missing precision