4
draw it out it helps
All of them.
rhombus
18
Two triangles
You can divide a quadrilateral up into as many triangles as you want, but at least two.
It's entirely possible to draw a quadrilateral with 3 acute angles.The fourth angle must be obtuse or reflex, but so what ? !
none the diagonal will always be bigger than a side
2
Infinitely many. Any triangle inside a quadrilateral can be divided into two without affecting the quadrilateral but increasing the number of triangles by 1. And then one of those triangles could be spilt into two and so on - without end.
You can put 2 triangles in a square or you can call it a quadrilateral.
8
you can basically draw an infinite amount of triangles in a dodecagon....
A straight line can intersect the side of a convex quadrilateral in at most two points and so divided it into at most two segments. A concave quadrilateral (an arrowhed or chevron) can be divided into three if the line touches the reflex vertex and cuts off the two "barbs" of the arrowhead. But 4 triangles is not possible.
it's impossible to have a quadrilateral that can't be cut into triangles.
4