Update index.html

Author: Gmac4247

index.html

@@ -1848,7 +1848,7 @@ <h6 style="font-size:160%;margin:7px">Area of a circle</h6>
 The edge length of the cube, which has the same volume as the sphere, equals the square root of the area of the square that has the same area as the sphere's cross section.
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-V = \left( \sqrt{3.2} \cdot r \right)^3
+  \[ V = (\sqrt{3.2} \cdot r)^3 \]
 </p>
 </div>
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