# Question Video: Determining Whether a Polygon Is Concave or Convex Mathematics • 8th Grade

Is this polygon concave or convex?

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### Video Transcript

Is this polygon concave or convex?

To answer this question, we’re going to need to remind ourselves of what it means to say a polygon is concave and what it means to say a polygon is convex.

A concave polygon is a polygon with one or more interior angles measuring more than 180 degrees. A convex polygon, on the other hand, is a polygon with all interior angles measuring less than 180 degrees.

So to be able to use these definitions of concave and convex polygons, let’s also remind ourselves of what an interior angle is. An interior angle is an angle inside a polygon at one of its vertices. So all of these angles inside this polygon are interior angles. We can see that these angles range from 90 degrees up to 140 degrees.

Therefore, all of the interior angles of this polygon measure less than 180 degrees. And so, this polygon is convex.