作为程序员，没有合适的工具，就得手搓一个，PC端，移动端均可适用。废话不多说，直接上代码。
HTML:
<div class="calculator"><label for="radius">圆的半径 (r)：</label> <input id="radius" type="number" placeholder="输入圆的半径"> <label for="angle">圆心角 (θ，以弧度为单位)：</label> <input id="angle" type="number" placeholder="输入圆心角（单位：弧度）"><button onclick="calculateArcLength()">计算弧长</button><div id="result" class="result">弧长结果将显示在这里</div></div>
JS:
functioncalculateArcLength() {constradius =parseFloat(document.getElementById('radius').value);constangle =parseFloat(document.getElementById('angle').value);if(isNaN(radius) ||isNaN(angle) || radius <=0|| angle <=0) {document.getElementById('result').textContent="请输入有效的半径和圆心角。";return; }constarcLength = radius * angle;document.getElementById('result').textContent=`弧长为：${arcLength.toFixed(2)}单位长度`; }
CSS:
.calculator{width:300px;background-color:#333;color: white;padding:20px;border-radius:10px;box-shadow:05px15pxrgba(0,0,0,0.3);}label{display: block;margin-bottom:10px;font-size:16px;}input, select {width:100%!important;padding:10px!important;margin-bottom:20px;color:#000000;border-radius:5px;border:1pxsolid#555;font-size:16px!important;background-color:#ffffff!important;}button{width:100%;padding:10px;background-color:#007bff;color: white;border: none;border-radius:5px;cursor: pointer;font-size:16px;}button:hover{background-color: orange;}.result{margin-top:20px;text-align: center;font-size:18px;}option {background-color:#ffffff;}p{font-size:18px;margin-top:5px!important;}
线上运行，可以直接打开：弧长计算器
