Question

Which of the following are concave polygons?

• A. i, ii, iii
• B. ii, iii, iv
• C. ii, iii
• D. none of these

Answer 1

The correct option is C

ii, iii

A concave polygon is a polygon in which at least one of the interior angles is greater than ${180}^{\circ }$. In a concave polygon at least one of the diagonals is exterior to the polygon.

In the above figures, figure (ii) and (iii) are concave polygons since both have a diagonal exterior to the polygon.

A convex polygon is a polygon in which all the interior angles are less than ${180}^{\circ }$. In a convex polygon, all the diagonals are interior to the polygon. Figure (i) is a convex polygon since all the interior angles are less than ${180}^{\circ }$.