unit circle radius of 5 code example

Example 1: border-radius circle using %

.circle {
    background-color:#fff;
    border:1px solid red;    
    height:100px;
    border-radius:50%;
    -moz-border-radius:50%;
    -webkit-border-radius:50%;
    width:100px;
}
<div class="circle"></div>

Example 2: circumference of a circle with a radius of 23.56

const number = 23 //or any number you like
Math.floor(number * (2 * Math.PI)