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 man and woman standing with luggage in a waiting area'. Reverse all words of length '7' in the given sentence.
Example Output: a man and woman standing with egaggul in a gnitiaw area

Example Input: Sentence: 'a man and a woman wearing all black are sitting next to each other on a bench'. Reverse all words of length '4' in the given sentence.
Example Output: a man and a woman wearing all black are sitting txen to hcae other on a bench

Example Input: Sentence: 'a guy in midair motion with several others in a grassy field in front of some sports nets'. Reverse all words of length '6' in the given sentence.
Example Output:
a guy in riadim noitom with several srehto in a yssarg field in front of some strops nets