Activity 1.2 Decomposing Polygons into Triangles
YOUR TASK
Decompose polygons into triangles, determine the relationship between the number of sides of the polygons and the number of triangles, apply this relationship to solve problems, justify your answer, and create your own problem solving task.
The applet below shows different polygons. Select the number of sides for the polygon, by adjusting the SLIDER 
. Use the SEGMENT tool 
to dissect or decompose the polygon. You can also use the POINT tool 
if you want to use other starting position for dissecting the polygon.
Record the results in the table provided below the applet then answer the questions.
. Use the SEGMENT tool to dissect or decompose the polygon. You can also use the POINT tool if you want to use other starting position for dissecting the polygon.
Record the results in the table provided below the applet then answer the questions.RECORD Data
IDENTIFY relationships
Examine the data in the table. In what way is the number of sides of the polygon related to the number of triangles?
SOLVE a problem
If you decompose a 20-sided polygon into triangles, how many triangles can you make?
JUSTIFY
Explain why you think your answer to the 20-sided polygon problem is correct.
SOLVE a problem
A polygon can be decomposed into 20 triangles. How many sides does the polygon have?
Select all that apply
- A
- B
- C
- D
- E
JUSTIFY
Explain why you think your answer to the decomposition of a polygon into 20 triangles problem is correct.
POSE a problem
Write a problem you want your classmates to solve involving decomposing polygons into triangles.
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Co-developer
Erlina Ronda