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 child is skateboarding and the man is jogging in the park'. Reverse all words of length '7' in the given sentence.

the child is skateboarding and the man is gniggoj in the park