JavaScript > Math Reference

PI number (PI) in JavaScript

How to return the PI value in JavaScript?


PI Property

The number PI (π) is a mathematical constant, the ratio of a circle cirumference to its diameter. It is represented by the Greek letter "π" since the 18th century and spelled as 'pi' some times. PI (π) is an irrational number and it cannot be expressed exactly as a fraction. 

The PI property returns the ratio of a circle's area to the square of its radius, which is approximately 3.14159.

<p>Click the below button to return PI.</p>
<input type="button" onclick="myNumber()" value="Click">
<p id="myId"></p>

<script>
    function myNumber() {
        document.getElementById("myId").innerHTML = Math.PI;
    }
</script>

In the above code snippet we have given Id as "myId"to the second <p> element in the HTML code. There is a function myNumber() in the<script>block which is connected to the onclick of the HTML button. We need to return the ratio of a circle's area to the square of its radius, for that we are using PIproperty. Onclick of the button "Click" in the HTML code fires the function myNumber() in the <script> block, at the same time Math.PI property returns the ratio of circle's area to the square of its radius as output.

OUTPUT

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