Question

Can someone tell me what "convex" and "concave" mean in geometry?

Answer 1

A concave polygon will always have an interior angle with a measure that is greater than 180 degrees.

Answer 2

A simple polygon is strictly convex if every internal angle is strictly less than 180 degrees. Equivalently, a polygon is strictly convex if every line segment between two nonadjacent vertices of the polygon is strictly interior to the polygon except at its endpoints.

Answer 3

So if I have to determine if a heptagon is convex, what should I look for?