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 adjective form of triangle is triangular.
If you're talking about adjective, like in parts of speech, then the word 'right' is the adjective, describing the noun 'triangle'.
Triangular.
Yes, the word triangular (having the shape of a triangle) is an adjective.
equilateral
Tri is the prefix of the word Triangle. ex: triathlon
Assuming that you meant midpoint, it is a median.
Literally "equiangular"; but since a triangle with all angles equal must have all sides equal, it is also "equilateral" and it is the second adjective that is used.
I think the question you mean to ask is, "Do three collinear points make a triangle?" Linear is simply the adjective form of "line", "collinear" is used to describe points that lie on the same line. (Two points not only can be collinear, but always are, so it makes little sense to describe them as such).Collinear points cannot make a triangle, a triangle requires three noncollinear points.
A triangle must be convex, so that adjective is redundant. The sum of the exterior angles of any polygon, whether convex or concave, an no matter how many sides, is 2*pi radians. That is equal to 360 degrees.
any triangle is a triangle
If a triangle is obtuse, the orthocenter of the triangle actually lies outside of the triangle. If the triangle is acute, the orthocenter of the triangle lies on the inside of the triangle