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我是Java新手。我試圖使用下式來計算三角形的面積:計算三角形的面積
S =(側1 +側2 +側3)/ 2
面積=平方根(側( - 側)(側 - side2)(side - side3)
如果用戶輸入三點: 1.5 -3.4 4.6 5 9.5 -3.4那麼三角形的面積應該是33.6但是,我的程序運行,但它給我不正確的答案,下面是我的代碼
// Import Java Scanner
import java.util.Scanner;
import java.lang.Math;
public class Ex_2_19 {
public static void main(String[] args) {
//Create a Scanner object
Scanner input = new Scanner(System.in);
float side = 0;
float area1 = 0;
float area2 = 0;
float area3 = 0;
float area4 = 0;
float calculatedarea = 0;
//Prompt the user to enter three points of a triangle
System.out.println("Enter point x1:");
System.out.println("Enter point y1:");
System.out.println("Enter point x2:");
System.out.println("Enter point y2:");
System.out.println("Enter point x3:");
System.out.println("Enter point y3:");
//Define the variables
float Pointx1 = input.nextFloat();
float Pointy1 = input.nextFloat();
float Pointx2 = input.nextFloat();
float Pointy2 = input.nextFloat();
float Pointx3 = input.nextFloat();
float Pointy3 = input.nextFloat();
//Formula to calculate the area of a triangle
side = (Pointx1 + Pointy1 + Pointx2 + Pointy2 + Pointx3 + Pointy3)/2;
area1 = side - (Pointx1 + Pointy1);
area2 = side - (Pointx2 + Pointy2);
area3 = side - (Pointx3 + Pointy3);
area4 = side * area1 * (area2) * (area3);
calculatedarea = (float) (Math.sqrt(area4));
//calculatedarea = (float) (Math.sqrt(area1)*(area2) * (area3));
//Print result
System.out.println("The area of the triangle is " + calculatedarea);
}
}
您正在使用的公式適用於三角形邊的長度。你只是將每個點的X和Y座標加起來 - 與長度無關。 –
基於https://www.mathsisfun.com/geometry/herons-formula.html,通過計算每對xy座標之間的距離來查找長度a,b,c。你計算區域1,2,3,4的方式似乎是錯誤的。 – Gosu