Grade Level(s):9th -12th grade

Subject(s):Math, Language Arts

Learner Outcomes:
Each student will be able to identify and name polygons according to the number of sides.
Each student will be able to distinguish between concave and convex polygons.
Each student will spend some time experimenting with the TI-92 calculator.

Duration of the Lesson:  2     50 minute periods.
Materials: Overhead projector, supplies, worksheet, TI- 92 calculator
                             and textbook..

Technology: TI-92 calculator, computer if available.

Procedures:
Define  polygon, consecutive vertices, consecutive sides, diagonals, and regular polygon.
Polygon will define convex and concave polygons.
The word polygon is derived from the Greek word meaning "many angled."
A polygon is a closed figure formed by a finite number of coplanar segments such that:
        1. the sides that have a common endpoint are noncollinear and,
        2. each side intersects exactly two other sides, but only at their endpoints.
Consecutive angles are two angles with one side in common.
Adjacent or consecutive sides are sides that intersect.
Adjacent or  consecutive vertices are vertices of  consecutive angles.
A diagonal  is a segment that joins two nonconsecutive sides.
A convex polygon is a polygon such that no line containing a side of the polygon contains a point in the interior of the polygon.
A polygon that is not convex is nonconvex or concave.
Concave and convex polygons.
Polygons may be classified by the number of sides they have. The chart at the right gives some common names for polygons.   In general, a polygon with n sides is called an n-gon.  This means that the nonagon can also be called a 9-gon.
 
Number of sides                             Polygon
 

3	Triangle
4	Quadrilateral
5	Pentagon
6	Hexagon
7	Heptagon
8	Octagon
9	Nonagon
10	Decagon
12	Dodecagon
n	n-gon

ABCDE and pentagon EABCD are two possible correct names for the polygon at the right .When referring to a polygon, we use its name and list the vertices in consecutive order.

In pentagon ABCDE, all the sides are congruent, and all the angles are congruent.  When a polygon has these characteristics, it is called a  regular polygon.

Lesson Extension:
        Using the TI-92 students will conduct the Introductory Lesson to TI-92.

Lesson Enrichment:Prefixes / Mobile ( Connection with Language Arts )
Evaluation/Assessment
 
 

 Letter Grade                          Minimum requirements 

In order to receive an "A"	Student will need to complete assigned work with 93% accuracy.
In order to receive a "B"	Student will need to complete assigned work with 83% accuracy.
In order to receive a "C"	Student will need to complete assigned work with 73% accuracy.
In order to receive a "D"	Student will need to complete assigned work with a minimum of 60% accuracy

National Standards
Understands that objects and relations in geometry correspond directly to objects and relations in algebra (e.g., a line in geometry corresponds to a set of ordered pairs satisfying an equation of the form ax + by = c).
State Standards
G.89,10,11 explore and identify properties of quadrilaterals and verify properties for parallelogram, rectangle, rhombus, square, and trapezoid
G.159,10,11 discover the lengths of sides of polygons from given data
G.23 use appropriate software to practice and master Geometry and Applied Geometry instructional objectives

References:
                 Glencoe Geometry: Integration, Applications, Connections
                       Geometry Puzzles
 
 

Terry J. Ash

Jeanina Butcher Ice

Mary Jo Roman