Question 699712
Convex polygon:

 definition: A polygon that has all {{{interior}}} angles {{{less}}} than {{{180}}}°

Note that a triangle (3-gon) is always convex, and a triangle is a polygon. A polygon is any closed figure made up of {{{3}}} or more line segments.

if you mean a convex polygon to have a sum of {{{interior}}} angles {{{180}}}°, than yes, it is a triangle.