In this task, you need to reverse all words of a given length in the sentence. The number of letters in a word determine its length. For example, the length of the word "apple" is 5.

Example Input: Sentence: 'a fire hydrant placed in the street just off the curb'. Reverse all words of length '3' in the given sentence.
Example Output: a fire hydrant placed in eht street just ffo eht curb

Example Input: Sentence: 'a women who is playing tennis on a tennis court'. Reverse all words of length '7' in the given sentence.
Example Output: a women who is gniyalp tennis on a tennis court

Example Input: Sentence: 'a train engine traveling down train tracks through a countryside'. Reverse all words of length '4' in the given sentence.
Example Output:
a train engine traveling nwod train tracks through a countryside