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: 'people watching a music concert being performed on a stage'. Reverse all words of length '5' in the given sentence.
Example Output: people watching a cisum concert gnieb performed on a egats

Example Input: Sentence: 'a group of people para sailing on a beach'. Reverse all words of length '5' in the given sentence.
Example Output: a puorg of people para sailing on a hcaeb

Example Input: Sentence: 'a woman is standing in the sun with an umbrella'. Reverse all words of length '5' in the given sentence.
Example Output:
a namow is standing in the sun with an umbrella