<p>Known to be or Known as ??
Thank You !</p>
<p>Both are correct.</p>
<p>When to use each of them ??</p>
<p>This story is known to be true.</p>
<p>Jeff is also known as Jeffrey.</p>
<p>Different meanings:</p>
<p>“This man is known to be a great guy.” ← WE KNOW he is a great guy.</p>
<p>“This man is known as a great guy.” ← Everyone refers to the man as a great guy, but we don’t know for sure that he really is one.</p>
<p>easier way to differentiate them ,
“known to be” should be followed by an adjective
"known as " should be followed by a noun
this is for granted btw 
and came alot in identifying the error ques.</p>