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 skier is flying through the air while people watch'. Reverse all words of length '7' in the given sentence.
Example Output: a skier is flying hguorht the air while people watch

Example Input: Sentence: 'a large grouo of people riding on a bunch of motorcycles'. Reverse all words of length '5' in the given sentence.
Example Output: a egral ouorg of people riding on a hcnub of motorcycles

Example Input: Sentence: 'a woman who is standing under an umbrella'. Reverse all words of length '2' in the given sentence.
Example Output:
a woman who si standing under na umbrella