find the area of a regular polygon inscribed in a circle in go

Here's one way to find the area of a regular polygon inscribed in a circle in Go:

main.go
package main

import (
	"fmt"
	"math"
)

func main() {
	numSides := 6 // change this to the number of sides in the polygon
	radius := 5.0 // change this to the radius of the circle

	// calculate the side length of the polygon
	sideLength := 2 * radius * math.Sin(math.Pi/float64(numSides))

	// calculate the area of the polygon
	area := 0.5 * float64(numSides) * sideLength * radius

	fmt.Printf("The area of a regular %d-gon inscribed in a circle of radius %.2f is %.2f\n", numSides, radius, area)
}
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In this example, we first define numSides as the number of sides in the regular polygon and radius as the radius of the circle. We then use the formula sideLength = 2 * radius * sin(pi/n) to calculate the length of one side of the polygon. Finally, we use the formula area = 0.5 * n * sideLength * radius to find the area of the polygon, where n is the number of sides.

Note that we use math.Sin and math.Pi from Go's built-in math package to perform the necessary calculations.