Question

What is a concave quadrilateral ?

Answer 1

A quadrilateral may be convex or concave (see the diagram below.) A quadrilateral that is concave has an angle exceeding 180o. In either case, the quadrilateral is simple, which means that the four sides of the quadrilateral only meet at the vertices, two at a time.

Answer 2

A quadrilateral in which the measure of one of the interior angle is more than 180 degree is called concave quadrilateral

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