how to make poly render flat? triangles are showing but I don't have an edge connecting the vertices, I just want the poly to render as flat but it renders as 2 angled triangles. Also when i connect the vertices the opposite way it still creates an extrusion shown in render. I cant really think of anything besides maybe shading smooth but I don't think I should have to.
Christopher Bennett has given you a solution but if you want to keep a low-poly look for your object, you could give it Auto Smooth (Properties panel > Object Data > Normals).

When used with Shade Flat, Auto Smooth won't try to smooth between faces but only between the triangles within a face: