How to calculate the area and perimeter of common geometric shapes (circle, rectangle, triangle) in Go?

To calculate the area and perimeter of common geometric shapes in Go, you can use the following formulas and implement them in your Go code:

Circle:
- Area: A = π * r^2 (where r is the radius of the circle)
- Perimeter: P = 2 * π * r

package main

import (
	"fmt"
	"math"
)

func main() {
	radius := 5.0

	area := math.Pi * math.Pow(radius, 2)
	perimeter := 2 * math.Pi * radius

	fmt.Printf("Circle:\nArea: %f\nPerimeter: %f\n", area, perimeter)
}

Rectangle:
- Area: A = length * width
- Perimeter: P = 2 * (length + width)

package main

import "fmt"

func main() {
	length := 5.0
	width := 3.0

	area := length * width
	perimeter := 2 * (length + width)

	fmt.Printf("Rectangle:\nArea: %f\nPerimeter: %f\n", area, perimeter)
}

Triangle:
- Area: A = (base * height) / 2
- Perimeter: P = side1 + side2 + side3

package main

import "fmt"

func main() {
	base := 4.0
	height := 3.0
	side1 := 5.0
	side2 := 6.0
	side3 := 7.0

	area := (base * height) / 2
	perimeter := side1 + side2 + side3

	fmt.Printf("Triangle:\nArea: %f\nPerimeter: %f\n", area, perimeter)
}

You can customize the input values for each shape as per your requirement. The respective formulas will calculate the area and perimeter accordingly.