The adjective form of triangle is triangular.
Yes, it is. It is the adjective form of the noun treachery, which can mean villainy, perfidy, or disloyalty. But treacherous can also mean fraught with danger (a treacherous section of the road).
A Noun
NO!!! in modern English. However, it is a combination of 'tri' and 'angle'. Since 'tri' is NOT a word in modern English, then it does not make 'triangle a compound word. Do not confuse with 'try'. Triangle is split into 'tri' and 'angle'. 'Tri' from Latin meaning 'three(3)'. Hence 'triangle' means 'three angles'. Archaically this would be known as a 'Trigon'. 'Tri' ; three, and 'gon' from 'polygon' a 2-dimensional figure of any number of sides.
No. In most cases, like "He tripped," it's a past tense verb. It can also be used as an adjective, notably in "a tripped breaker."
The adverb form of the adjective 'tragic' is tragically.
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.
The noun form for the adjective authentic is authenticity.
The noun form of the adjective 'dangerous' is dangerousness.The word 'dangerous' is the adjective form of the noun danger.The noun form of the adjective 'childish' is childishness.The word 'childish' is the adjective form of the noun child.The noun form of the adjective 'beautiful' is beautifulness.The word 'beautiful' is the adjective form of the noun beauty.
The noun form of the adjective 'wide' is wideness.A related noun form is width.
Triangular.
The noun form of the adjective 'comfortable' is comfortableness.The word 'comfortable' is the adjective form of the noun comfort.
The noun form of the adjective 'modest' is modestness.A related noun form is modesty.
The abstract noun form for the adjective convenient is convenience.
The abstract noun form of the adjective unique is uniqueness.
The noun form for the adjective hilarious is hilariousness. A related noun form is hilarity.
The adjective form for the noun nation is national.
The noun form of the adjective close is closeness.