Update index.html

Calculator condition

Author: Gmac4247

index.html

@@ -3284,7 +3284,7 @@ <h3 itemprop="name" style="margin:7px">Area of a Circle Segment</h3>
   const length = parseFloat(document.getElementById('segment-length').value);
   const height = parseFloat(document.getElementById('segment-height').value);
 
-  if (isNaN(length) || isNaN(height) || height === 0) {
+  if (isNaN(length) || isNaN(height) || height === 0 || length === 0) {
     document.getElementById('segment-area').innerText = '';
     return;
   }