Activity Overview
In this activity, students use the Geoboard to determine the area of any polygon using coordinates.
Before the Activity
Start the Geoboard App and format it
See the attached PDF file for detailed instructions for this activity
Print pages 113 - 118 from the attached PDF file for your class
During the Activity
Distribute the page to the class.
Follow the Activity procedures:
Construct a heptagon using the coordinates of its vertices
Starting at any point and moving counterclockwise around the polygon, list the vertices in a vertical column in consecutive order
Repeat the starting point at the bottom of the list
Calculate D, the sum of the down diagonal products, and U, the sum of the up diagonal products
Determine the area of the polygon which is one-half of the difference between D and U
Construct a square, draw a diagonal, and a line segment that divides the square into four non overlapping regions
Find the ratios of the areas of the four regions
After the Activity
Students complete the Activity sheet and answer questions.
Review student results:
As a class, discuss questions that appeared to be more challenging
Re-teach concepts as necessary