Definition: 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.
Input: Sentence: 'the man in the red shirt is going to hit the ball with his racket'. Reverse all words of length '4' in the given sentence.

the man in the red shirt is going to hit the llab htiw his racket