Problem

A circle is drawn with 9 points on its circumference, as shown in the diagram below. A student creates polygons with 3 or more sides by connecting the points with straight lines.
The number of polygons that can be created that have at most 4 sides is

Answer

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Answer

Final Answer: The total number of polygons that can be created with at most 4 sides is \(\boxed{210}\).

Steps

Step 1 :A circle is drawn with 9 points on its circumference. A student creates polygons with 3 or more sides by connecting the points with straight lines.

Step 2 :We need to consider the number of ways to choose points on the circle to form polygons with 3 or 4 sides.

Step 3 :For a polygon with 3 sides (a triangle), we need to choose 3 points out of 9. This can be done in \(\binom{9}{3}\) ways, which equals to 84.

Step 4 :For a polygon with 4 sides (a quadrilateral), we need to choose 4 points out of 9. This can be done in \(\binom{9}{4}\) ways, which equals to 126.

Step 5 :The total number of polygons is the sum of these two quantities, which is \(84 + 126 = 210\).

Step 6 :Final Answer: The total number of polygons that can be created with at most 4 sides is \(\boxed{210}\).

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