Download 10.1 Naming Polygons

Geometry – Chapter 10 Lesson Plans
Section 10.1 – Naming Polygons
Enduring Understandings: The student shall be able to:
1. name polygons according to the number of sides and angles.
Standards:
22. Similarity
Identifies similar figures in practical applications; identifies similar triangles and
other similar polygons by using their properties.
Essential Questions: How do we identify polygons?
Warm up/Opener:
Activities:
Review definition of a polygon (closed figure, in a plane, formed by segments called
sides). A polygon is named by the number of its sides or angles. Include the definitions
of side, vertex, consecutive sides and vertices, diagonal (end points are non-consecutive
vertices).
They have to memorize the list on page 402:
Prefix
TriQuadricPentaHexa-
Number of
Sides
3
4
5
6
Name of
Polygon
Triangle
Quadrilateral
Pentagon
Hexagon
Prefix
HeptaOctaNonaDeca
Number of
Sides
7
8
9
10
Name of
Polygon
Heptagon
Octagon
Nonagon
Decagon
Review concave and convex polygons.
Define a regular polygon – congruent angles and sides.
Talk about what a perimeter is, and the perimeter of a regular polygon is the length of a
side times the number of sides.
How does the shape of a regular polygon change as we increase the number of sides? It
looks increasingly like a circle.
Assessments:
Do the “Check for Understanding”
CW WS 10.1 Practice of the Blue Book
HW pg 405-407, # 13-41 odd (15)