To determine the number of sides in a regular polygon inscribed in a circle of radius r with an area of 2r^2√2, the polygon is divided into n equal triangles. Each triangle's area can be calculated using the formula 1/2 * a * b * sin(C), where a and b are the lengths of two sides, and C is the included angle. By equating the total area of the n triangles to the given area of the polygon, a relationship can be established to solve for n. The discussion emphasizes the importance of understanding the geometric properties of inscribed polygons and the use of trigonometric formulas in calculating areas. Ultimately, the solution leads to finding the specific value of n that satisfies the area condition.