"The red fork is in the kitchen."
Translation:Aia ke ʻō ʻulaʻula ma ka lumi kuke.
UH 1st year 'ōlelo taught me to use "i" for "in motion/nebulous" circumstances and "ma" for more permanent conditions... By UH 3rd year 'ōlelo some but not great clarity has been developed... Without the complete quotation to better determine the circumstance of "this" room... my guess is the"condition" may be about the room's permanent location...
Ke vs. Ka "Ka", "Ke" and "Nā" are determiners that can sometimes be translated as "the". Use ke when the noun that follows begins with the letters K, E, A, or O. Use ka with almost all others! This is commonly referred to as the KEAO rule. However, there are exceptions to the above.
Not sure what rule you're talking about, but I'm guessing the issue is the contrast between
(1) "He ‘ō kēnā" -- "That is a fork"
(2) "Aia ke ‘ō ma ka lumi kuke" -- "The fork is in the kitchen"
Notice that the location in the first sentence is "kēnā" ("that", near the listener), which is a single word, while the location in the second sentence takes up most of the sentence, "ma ka lumi kuke".
The location sentences I've encountered on Duolingo so far fall into one of those two patterns.