How to convert ( 11011.0101 ) from binary to decimal?
The positions to the right of the point are treated the same way as the ones before: each step to the right halves the weight. Hence

binary   | decimal
------------------
100.     |    4
 10.     |    2
  1.     |    1
  0.1    |  1/2
  0.01   |  1/4
  0.001  |  1/8


With these weights you should be able to calculate the decimal value of any binary number, including ones like you show with a .