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 hand reaching out towards a standing giraffe'. Reverse all words of length '7' in the given sentence.
Example Output: a hand reaching out sdrawot a standing effarig

Example Input: Sentence: 'a person holding a yummy looking hot dog'. Reverse all words of length '7' in the given sentence.
Example Output: a person gnidloh a yummy gnikool hot dog

Example Input: Sentence: 'a group of brown horses standing on top of a green field'. Reverse all words of length '3' in the given sentence.
Example Output:
a group of brown horses standing on pot of a green field