1. Section 1.6 Two-Dimensional Figures

2.  Derived from a Greek word meaning “many sides”.  Polygon- closed figure formed by a finite number of coplanar segments called sides such that:  The sides that have a common endpoint are noncollinear  Each side intersects exactly two other sides  Vertex of the polygon- vertex of each angle

3.  Polygons are classified by the number of sides.  3-Triangle,9-Nonagon  4-Quadrilateral, 10-Decagon  5-Pentagon,11- Hendecagon  6-Hexagon, 12-Dodecagon  7-Heptagon  8-Octagon

4.  Polygons are named by the letters of its consecutive (in order) vertices.

5.  Concave- some lines (when extended) pass through the interior of the polygon  Convex- no points of the lines (when extended) are in the interior.

6.  Equilateral polygon - all sides are congruent.  Equiangular polygon - all angles are congruent.  Regular polygon - convex, equilateral, and equiangular.  Irregular – everything else

7.  Name each polygon by its number of sides, then state whether it is convex or concave, regular or irregular.

8.  Perimeter - sum of the lengths of all the sides  Units stay the same.  Circumference -distance around a circle  Units stay the same.  Area - number of square units needed to cover a surface  Units are squared.

9. TriangleSquareRectangleCircle Perimeter P = b + c +dP = 4sP=2l +2wC= π d Area A= 1/2bhA=s 2 A=lwA= π r 2

11.  Find the area and perimeter (or circumference) of each figure. 12.4ft 18.9ft 5cm 12cm 6m

12.  What is the perimeter of a rectangle if its length is half its width and its area is 48 in 2 ?

13.  Page 61: 1-10 all, 12- 26 evens,  32-42 evens