Triangular.
The adjective form of triangle is triangular.
The adjective form of the noun 'gas' is gaseous.
No, it is not. Triangle is a noun, a shape or anything with three sides. The adjective form is triangular.* In the popular historical term, triangle trade, it is acting as a noun adjunct in place of the adjective triangular.
"Nicaraguan"
Examples of adjectives that are formed from a noun are:air (noun) - airy (adjective)artist (noun) - artistic (adjective)beauty (noun) - beautiful (adjective)blood (noun) - bloody (adjective)fish (noun) - fishy (adjective)hope (noun) - hopeful (adjective)length (noun) - lengthy (adjective)memory (noun) - memorable (adjective)politics (noun) - political (adjective)thought (noun) - thoughtful (adjective)use (noun) - useful (adjective)water (noun) - watery (adjective)
The adjective form for the noun athlete is athletic.
It is a noun, formed from the adjective healthy+ness.
If you're talking about adjective, like in parts of speech, then the word 'right' is the adjective, describing the noun 'triangle'.
No. Loneliness is a noun formed from the adjective "lonely."
The adjective form is tempestuous.
The noun form for the adjective witty is wittiness. Another noun form is wit.
The noun form of the adjective is formed by adding the suffix -ness.The noun form is eloquentness.