learned the use of word "practicable"

While reading a news,i came to this word "practicable".Initially i thought,its some kind of printing mistake.The author probable meant "practical" because i never heard of the word "practicable" before.
Though after checking the dictionary,i was surprised."Practicable" is a separate adjective from "practical".

Definition:

1. capable of being done: capable of being carried out or put into effect

2. usable: capable of being used successfully

 So googled a bit after that.Got this nice example here-

practicable or practical? These two adjectives have overlapping meanings. Both indicate that something can be done, but practical also implies that it is appropriate, sensible, or useful: It is practicable to do the calculation in the traditional way, but far more practical to use a computer. The difference between impracticable and impractical is rather more clear-cut: impracticable means "impossible" and impractical means "not workable when put into practice."