the right side
convex
This means the vented of a circle. It is the radius of the circle that is perpendicular to a line tangent to any point on the concave side of a smooth curve.
Concave, because you can connect the corners from the outside.
concave
A concave circle
the right side
convex
The definition of concave is a curved like a segment of the interior of a circle or hollow sphere.
There are some meaning on the term " concave up". However, in most cases, a concave is a hallow curve. A half circle with an opening is also a concave. Concave up means to concave somethings.
*concave . curved like a segment of the interior of a circle or hollow sphere; hollow and curved
This means the vented of a circle. It is the radius of the circle that is perpendicular to a line tangent to any point on the concave side of a smooth curve.
it is a piece of glass where microscopic specimens are placed for observation. This slide has a circle in the middle with a convex side and a concave side. The sample should be placed in the depression- on the concave side.
concave
The opposite of convex is concave. Concave shapes have an inward curve, while convex shapes have an outward curve.
The circle is not a polygon because it is not composed of straight line segments.A star (outline shape) is actually an irregular concave decagon (5 pointed) or dodecagon (6 pointed).
This depends on your definition. One could say that circles ({p in R^n : d(p,m) = r}) are concave, while (open) disks ({p in R^n : d(p,m) < r}) are convex.