Investigating Geometry: Polygons

Henrico County Public Schools

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May 2006

Lesson 3-4: Polygons

Interactive Applet

Video Lecture - part one


Video Lecture - part two

Objective:

SOL G.10: The student will solve real-world problems involving angles of polygons.

 Applet Directions 1 Close 
  1. Construct a regular hexagon inscribed within Circle B.

  2. Using the cirle tool , construct a circle with radius AB and center at point A.

  3. Again, using the same tool, make congruent circles (radius AB ) but with centers located at the insections of the circles from step above.

  4. Repeat this process until there are a total of 7 circles: the given circle at center B and 6 others with centers that are on circle B.
 Applet Directions 2 Close 
  1. Connect the centers of the 6 circles with the segment tool .

  2. The correct completed construction will look like this image .

  Other Web Sites web Close 
  1. Glencoe: On Line Quiz
 Hands-On Activities Close 
  1. Explore Exterior Angles
  2. Explore Interior Angles
  3. Create a Trapezoid C.a.R.
 Puzzles & Problems tangram Close 

1. Let x, y, and z represent the measures of an exterior angle of a regular 20-gon, a regular decagon, and a regular dodecagon, respectively. Without calculating exact measures, arrange x, y, and z in order from least to greatest. Explain your reasoning.

2. Each of the measures of the interior and exterior angles of a regular polygon are in the ratio of 5:1. Find the measures of an interior and an exterior angle and the name of the polygon.