Use js to quickly find the area of a triangle-JS Tutorial-php.cn

Use js to quickly find the area of a triangle

藏色散人

Release： 2021-08-06 18:04:17

Original

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Everyone should know the formula for the area of a triangle, that is, the area is equal to one-half times the base times the height. Haha, it doesn’t matter if you forget. This article will introduce to you how to calculate the area of a triangle using js.

First of all, let me give you a brief introduction to the triangle area formula:

The triangle area formula refers to using a formula to calculate the area of a triangle, three line segments in the same plane and not on the same straight line The closed figure formed by connecting end to end is called a triangle, and its symbol is △.

As shown below:

Use js to quickly find the area of a triangle

So after briefly understanding the triangle area formula, let me ask you a question: "Please write a JavaScript function to calculate The area of a triangle whose three sides have lengths 4, 5, and 6”.

I don’t know if you have any calculation ideas~

The following is the method I gave:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
<script>
    var side1 = 4;
    var side2 = 5;
    var side3 = 6;
    var s = (side1 + side2 + side3)/2;
    var area =  Math.sqrt(s*((s-side1)*(s-side2)*(s-side3)));
    console.log(area);
</script>
</body>
</html>

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The calculation result is:

9.921567416492215

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In fact, this is a Math problem!

However, one knowledge point that everyone needs to master is Heron's formula. Heron's formula is also translated as Heron's formula, Hailong formula, Hero's formula, and Heron-Qin Jiushao formula; it is calculated directly by using the side lengths of the three sides of a triangle. The formula for the area of a triangle; the expression is: S=√p(p-a)(p-b)(p-c).

The popular explanation is:

It is known that the three sides are a, b, and c. The side lengths of our example here are 4, 5, and 6 respectively;

Let p= (a b c)/2, that is, the "(side1 side2 side3)/2"

area in the code is S=√[p(p-a)(p-b)(p-c)], It is "Math.sqrt(s*((s-side1)*(s-side2)*(s-side3)));".

You need to know a function here, which is the Math.sqrt() function, which is used to return the square root of a number;

→Note: Since sqrt is a static method of Math , so it should be used like this: Math.sqrt(), not as a method of the Math instance you created.

Finally, I would like to recommend "JavaScript Basics Tutorial" ~ Welcome everyone to learn ~

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