Questions & Answers about Der Plan ist machbar.
In German, every noun has a grammatical gender that you simply have to learn with the noun.
Plan is masculine in German, so it takes the masculine definite article der in the nominative singular:
- der Plan – the plan (masculine, singular)
- die Pläne – the plans (plural)
There is no logical reason why it’s der instead of die or das; it’s just part of the word’s dictionary entry:
- der Plan, die Pläne
Machbar is a predicate adjective here, used after the verb sein (ist).
German adjectives are:
- inflected (get endings) when they come directly before a noun:
- ein machbarer Plan – a feasible plan
- der machbare Plan – the feasible plan
- uninflected (no endings) when used after sein, werden, bleiben, etc.:
- Der Plan ist machbar. – The plan is feasible.
- Der Plan bleibt machbar. – The plan remains feasible.
So after ist, the correct form is the bare adjective machbar with no ending.