いい加減(ii kagen) has some different meanings.https://dictionary.goo.ne.jp/word/%E5%A5%BD%E3%81%84%E5%8A%A0%E6%B8%9B...
1-2 ; 相当な程度に達しているので、ほどほどのところで終わってほしいさま。
Bc it has reached a considerable degree, someone wants you to finish at a moderate level,
The phrases when asking conclusions or results from people who have been worried for a long time.
We use it when angry, but that's not all as emotion/feeling, just wondering cases also usual.
It is often used when you want to know the results, but it is also used to check the progress.
So the answer is "Already V(past = decided)?" as longer time has passed.
And, we also use "もう(mou : sounds like long tone "もー mo")" instead of いい加減.
This "V(past)+か(ka)" is limited to whether the people are younger than speaker or an equal position,
Since いい加減 often includes a bad meaning(like disappointing), it cannot be used for unfamiliar partners.
otherwise, use honorific(敬語 keigo) like "もうお決まりですか? (mou okimari desuka?)"
or "もうお決めになられましたか? (mou okime ni nararemasita-ka?)".
Basically, -か is used not only for "question" but also for "emphasis".
In this case, the emphasis is strong and "の(no)" can be substituted.
Conversely, いい加減(もう) can be used as the same meaning even if か is omitted.
- もう決まったのか？ meanings are all same,
but in some cases, it does not mean a strong tone, but an emotion of "anger".