Write a program that prompts the user to enter the length from the center of a pentagon to a vertex and computes the area of the pentagon, where r is the length from the center of a pentagon to a vertex.
(Hint: Length of the side =2*length from the center to a vertex * sine(PI/5)
Area = (5 * Math.pow(side, 2)) / (4 * Math.tan(Math.PI /5));
For rounding to two decimal points uses String.format(“%.02f”,variablename))
Input:
length from center: 6.4
Output:
Area = 97.39
import java.io.*; import java.util.*; import java.lang.Math; public class temp{ public static void main(String[] args){ double verside , side , area; Scanner scan = new Scanner(System.in); System.out.print("Length from center to vertex: "); verside = scan.nextDouble(); side = 2*verside*Math.sin(Math.PI/5); area = (5*Math.pow(side,2))/(4*Math.tan(Math.PI/5)); System.out.println("Area of Pentagon: "+String.format("%.02f",area)); } }
INPUT_1:
Length from center to vertex: 6.4
OUTPUT:
Area of Pentagon: 97.39
INPUT_2:
Length from center to vertex: 5.9
OUTPUT:
Area of Pentagon: 82.77
INPUT_3:
Length from center to vertex: 6.3
OUTPUT:
Area of Pentagon: 94.37
INPUT_4:
Length from center to vertex: 5.2
OUTPUT:
Area of Pentagon: 64.29
INPUT_5:
Length from center to vertex: 11.2
OUTPUT:
Area of Pentagon: 298.25
ILLUSTRATION