JSFiddle - React, Tailwind, and code Playground

JavaScript

console.clear();

function getPPI(){
    var div, body, ppi;
    
    div = document.createElement("div");
    div.style.width="1in";
    
    body = document.getElementsByTagName("body")[0];
    body.appendChild(div);

    ppi = document.defaultView.getComputedStyle(div, null).getPropertyValue('width');

    body.removeChild(div);

    return parseFloat(ppi);
}


var d = Math.floor( Math.sqrt( Math.pow(window.screen.height,2) + Math.pow(window.screen.width,2) ) / getPPI() );

console.log(d);