2. 1)The locus of points, lying in a plane, that are equidistant from a specific point – the center. 2)A regular polygon with an infinite number of sides. 3)A 360 degree arc. DEFINITION OF A CIRCLE…

3. A polygon is a closed, two dimensional figure composed of straight lines that meet at the figure’s vertices. DEFINITION OF A POLYGON

4. SCALENE -- polygon with all sides having different lengths EQUILATERAL – polygon with all sides having the same length EQUIANGULAR -- a polygon with all angles having the same measurement. REGULAR -- a polygon that is both equilateral and equiangular QUALITIES OF POLYGONS

5. TANGENTIAL – a polygon whose inscribed circle is tangent to all sides. CYCLIC – a polygon whose circumscribed circle is touched by all of the vertices of the polygon. BICENTRIC – a polygon that is both tangential and cyclic. QUALITIES OF POLYGONS

6. POLYGON NAMING Polygons are named according to the number of sides they have. 3 sides – triangle 4 sides – quadrilateral 5 sides – pentagon 6 sides – hexagon 7 sides – septagon 8 sides -- octagon

7. ALL TRIANGLES ARE BICENTRIC ALL triangles are tangential. All triangles are cyclic.

8. THEREFORE ALL TRIANGLES ARE BICENTRIC.

9. The Platonic Solids are convex polyhedra with faces composed of congruent convex regular polygons. There are exactly five such solids – hexahedron, dodecahedron, icosahedron, octahedron and the tetrahedron. NOW ON TO THE PLATONIC SOLIDS

10. All of the vertices of a platonic solid lie on a sphere. All of the dihedral angles are equal. All of the faces are regular congruent polygons. All of the vertices are surrounded by the same number of faces. QUALITIES OF THE PLATONIC SOLIDS

11. It has 4 Faces Each face is an Equilateral TriangleEquilateral Triangle It has 6 Edges It has 4 Vertices (corner points) and at each vertex 3 edges meet TETRAHEDRON FACTS

12. TETRAHEDRON NET

13. HEXAHEDRON FACTS