This is the 6073rd most frequent Korean word.
설명한
"Explained."
Here, '설명한' (explained) is describing '내용' (content), specifying the content has been explained earlier.
설명한 내용을 다시 한번 확인해 보세요.
Please check the explained content once again.
In this sentence, '설명한' refers to the method ('방식') explained by the teachers, used to describe the nature of how it has been explained and presented.
지금까지 교사들이 설명한 방식은 효과적이었다.
The method that teachers have explained so far has been effective.
In this sentence, '설명한' (explained) is used as a past participle adjective modifying the noun '보고서' (report), indicating the report has been explained.