1. 3D Solids Vocabulary 6 th Grade Math

2. Polygon A polygon is a closed figure formed by three or more line segments.

3. Examples of Polygons

4. These Figures ARE NOT Polygons Why is this figure not a polygon? It is not made of 3 or more line segments! Why is this figure not a polygon? It is not CLOSED!

5. Face A face is a flat surface of a 3-dimensional figure.

6. This is a face. This face is a polygon. This is a face. It is circular and may also be called a base.

7. Edge An edge is a line segment where two faces or a face and lateral surface of a 3-dimensional figure meet.

8. Think about this… Where do we find the edges on a 3- dimensional figure?

9. This figure has many edges …and one more that we can’t see!

10. Does this figure have any edges? Yes… because the faces meet the lateral surface. Face or circular base Lateral Surface

11. Vertex (plural – Vertices) A point… 1) Where three or more edges of a polyhedron meet. 2) Opposite the base of a cone.

12. This triangular pyramid has 4 vertices.

13. Does this cone have a vertex? Yes! It does have a point opposite of the face or circular base – therefore it does have a vertex!

14. Base base of a cone – flat circular part, which may also be called a face base of a pyramid - polygonal region that does not intersect with other faces at the vertex

15. Bases, cont. bases of a prism – the two parallel and congruent regions bases of a cylinder – the two parallel, circular regions

16. Cylinder A cylinder is a 3-dimensional figure with two parallel, circular bases or faces.

17. Cone A cone is a 3-dimensional figure with a circular base or face.

18. Prism A prism is a 3- dimensional figure with two parallel, congruent bases, and all faces that are parallelograms (rectangles, etc.).

19. Naming Prisms Prisms are named by the shape of their bases (the two sides that are congruent and parallel). triangular prism pentagonal prism

20. Pyramids A pyramid is a 3-dimensional figure with one base and triangular faces.

21. Naming Pyramids A pyramid is named by the shape of its base. triangular pyramid

22. Definitions adapted from… http://intermath.coe.uga.edu Geometry to Go, published by Great Source Teaching Student Centered Mathematics, Grades 5-8, by John Van de Walle & LouAnn H. Lovin