I have to find the areas of a triangle using Heron's formula. I wrote this code but it is not calculating the area correctly.
For example I input sideA= 5, sideB= 4, sideC= 3 and the answer is supposed to be 6 but instead I get 72088
Can anybody help me fix this and explain why its happening?
function Triangle(sideA, sideB, sideC) {
this.sideA = sideA;
this.sideB = sideB;
this.sideC = sideC;
this.semiP = ((this.sideA + this.sideB + this.sideC) / 2);
this.area = function() {
return (Math.sqrt(this.semiP * ((this.semiP - this.sideA) * (this.semiP - this.sideB) * (this.semiP - this.sideC))));
}
}
function calculate() {
var sideA = document.getElementById('sideA').value;
var sideB = document.getElementById('sideB').value;
var sideC = document.getElementById('sideC').value;
var myTriangle = new Triangle(sideA, sideB, sideC);
document.getElementById('results').innerHTML = "Area: " + myTriangle.area();
}<p>
Enter length of side a <input type='text' id="sideA" />
<br>
<br> Enter length of side b <input type='text' id="sideB" />
<br>
<br> Enter length of side c <input type='text' id="sideC" />
<div id="results"></div>
<button type="button" onclick="calculate()">Calculate</button>The problem that you are having is the sideA, B and C variables are all of type STRINGs and not anything numeric. There are a few different solutions, in my answer I chose to use parseFloat to allow you to have decimal points as input as well as whole numbers.
function Triangle(sideA, sideB, sideC) {
this.sideA = parseFloat(sideA);
this.sideB = parseFloat(sideB);
this.sideC = parseFloat(sideC);
this.semiP = ((this.sideA + this.sideB + this.sideC) / 2);
this.area = function() {
return (Math.sqrt(this.semiP * ((this.semiP - this.sideA) * (this.semiP - this.sideB) * (this.semiP - this.sideC))));
}
}
function calculate() {
var sideA = document.getElementById('sideA').value;
var sideB = document.getElementById('sideB').value;
var sideC = document.getElementById('sideC').value;
var myTriangle = new Triangle(sideA, sideB, sideC);
document.getElementById('results').innerHTML = "Area: " + myTriangle.area();
}<p>
Enter length of side a <input type='text' id="sideA" />
<br>
<br> Enter length of side b <input type='text' id="sideB" />
<br>
<br> Enter length of side c <input type='text' id="sideC" />
<div id="results"></div>
<button type="button" onclick="calculate()">Calculate</button>