Activity Overview
In this activity, students use the Geoboard to determine the areas of polygons by dissecting them into parts that are squares, rectangles, and triangles.
Before the Activity
Start the Geoboard App and format it
See the attached PDF file for detailed instructions for this activity
Print pages 51 - 60 from the attached PDF file for your class
During the Activity
Distribute the page to the class.
Follow the Activity procedures:
Construct a hexagon and find its area by counting squares and half squares
Find the area of a trapezoid by using a surrounding rectangle and check the answer using the calculator
Find the area of the trapezoid by dividing it into rectangles and triangles
Dissect triangles and ensure that every smaller triangle has at least one vertical or horizontal line segment as one of its sides, so that both the base and height of each triangle are whole numbers
Draw given shapes on the geoboard and find their area by using the dissection method
After the Activity
Student 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