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: 'looking down at skiers holding their skis on the ski slope'. Reverse all words of length '7' in the given sentence.
Example Output: gnikool down at skiers gnidloh their skis on the ski slope

Example Input: Sentence: 'a blue colored sign with a white arrow'. Reverse all words of length '1' in the given sentence.
Example Output: a blue colored sign with a white arrow

Example Input: Sentence: 'a red stop sign posted above a no parking sign'. Reverse all words of length '1' in the given sentence.
Example Output:
a red stop sign posted above a no parking sign