Identifying Polygons and Their Components
Identifying Polygons and Their Components introduces Grade 6 students to the definition and vocabulary of polygons: closed 2D figures made of three or more non-crossing straight line segments, with each segment called a side and each intersection called a vertex. Covered in Illustrative Mathematics Grade 6, Unit 1: Area and Surface Area, students learn to classify polygons by the number of sides and distinguish convex from non-convex polygons. This vocabulary is foundational for all subsequent work with 2D geometry and area.
Key Concepts
A polygon is a closed, two dimensional figure formed by three or more straight line segments that do not cross each other. Sides: The straight line segments that form the polygon. Vertices: The points where the sides meet (singular: vertex). Angles: The angles formed at the vertices inside the polygon.
Common Questions
What is a polygon?
A polygon is a closed 2D figure made of three or more straight line segments that do not cross each other. The segments are the sides and their intersection points are the vertices.
What makes a shape a polygon?
It must be closed (all sides connect), made of straight segments (no curves), and the segments must not cross each other.
What are the parts of a polygon?
A polygon has sides (the straight line segments), vertices (the corner points where sides meet), and interior angles (the angles inside at each vertex).
Where is identifying polygons in Illustrative Mathematics Grade 6?
This topic is in Unit 1: Area and Surface Area of Illustrative Mathematics Grade 6.
What is the difference between a convex and a non-convex polygon?
A convex polygon has all interior angles less than 180 degrees, so no part caves inward. A non-convex polygon has at least one interior angle greater than 180 degrees.