A three sided closed plane figure (shape) is a triangle.
A quadrilateral is a closed plane figure with four straight sides.
A polygon
A triangle whose sides are curved outwards.
Cjic
A three sided closed plane figure (shape) is a triangle.
It is a polygon
If they are straight sides, then a polygon. Otherwise, simply "a closed plane figure with 3 or more sides".
a triangle
It is a polygon that is a closed plane figure with 3 or more straight lines.
If none of the sides ever cross each other, there cannot be a closed plane figure.
A quadrilateral is a closed plane figure with four straight sides.
A polygon
A quadrilateral.
Polygon
A polygon
It is a polygon