These elements construct radicals. The msqrt element is used for square roots, while the mroot element is used to draw radicals with indices, e.g. a cube root. MathML Fundamentals
<math mathsize="45">
<mspace linebreak="newline" indentalign="center"></mspace>
<mtext style="border:1px;" mathsize="50">MathML Fundamentals - msqrt, mroot</mtext>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow style="border:1px;">
<mtext>aaa</mtext>
<msqrt style="border:1px">
<mrow style="border:1px">
<mi style="border:1px">aagg</mi>
<mo>+</mo>
<mspace style="border:1px" width="10"></mspace>
<mi style="border:1px">ABC</mi>
<mspace style="border:1px" width="10" height="0" depth="10"></mspace>
<mi style="border:1px">ABC</mi>
</mrow>
</msqrt>
</mrow>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow style="border:1px;" dir="rtl">
<mtext>aaa</mtext>
<msqrt style="border:1px">
<mrow style="border:1px">
<mi style="border:1px">aagg</mi>
<mo>+</mo>
<mspace style="border:1px" width="10"></mspace>
<mi style="border:1px">ABC</mi>
<mspace style="border:1px" width="10" height="0" depth="10"></mspace>
<mi style="border:1px">ABC</mi>
</mrow>
</msqrt>
</mrow>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow style="border:1px;">
<mtext>aaa</mtext>
<msqrt>
<msqrt style="border:1px">
<msqrt style="border:1px">
<msqrt style="border:1px">
<msqrt style="border:1px;padding:2px">
<msqrt style="border:1px">
<mi style="border:1px">ABC</mi>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</mrow>
<mstyle style="border:1px;" sqrtthickness="50%">
<mtext>aaa</mtext>
<msqrt>
<msqrt style="border:1px">
<msqrt style="border:1px">
<msqrt style="border:1px">
<msqrt style="border:1px;padding:2px">
<msqrt style="border:1px">
<mi style="border:1px">ABC</mi>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</mstyle>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow style="border:1px;">
<mtext>aaa</mtext>
<msqrt closed="true">
<msqrt style="border:1px" closed="true">
<msqrt style="border:1px" mathbackground="red" closed="true">
<msqrt style="border:1px" closed="true">
<msqrt style="border:1px;padding:2px" closed="true">
<msqrt style="border:1px" closed="true">
<mfrac style="border:1px">
<mi style="border:1px">ABC</mi>
<mi style="border:1px">ABC</mi>
</mfrac>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</mrow>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow style="border:1px;" dir="rtl">
<mtext>aaa</mtext>
<msqrt closed="true">
<msqrt style="border:1px" closed="true">
<msqrt style="border:1px" mathbackground="red" closed="true">
<msqrt style="border:1px" closed="true">
<msqrt style="border:1px;padding:2px" closed="true">
<msqrt style="border:1px" closed="true">
<mfrac style="border:1px">
<mi style="border:1px">ABC</mi>
<mi style="border:1px">ABC</mi>
</mfrac>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</msqrt>
</mrow>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow style="border:1px;">
<mtext mathsize="49">aaa3</mtext>
<mroot style="border:1px">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">12</mn>
</mroot>
</mrow>
<mrow style="border:1px;">
<mtext mathsize="49">aaa3</mtext>
<mroot style="border:1px">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">124567</mn>
</mroot>
</mrow>
<mrow style="border:1px;" dir="rtl">
<mtext mathsize="49">aaa3</mtext>
<mroot style="border:1px">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">124567</mn>
</mroot>
</mrow>
<mrow style="border:1px;" dir="rtl">
<mtext mathsize="49">aaa3</mtext>
<mroot style="border:1px">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">12</mn>
</mroot>
</mrow>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow style="border:1px;">
<mtext mathsize="49">aaa3</mtext>
<mroot style="border:1px" closed="true">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">12</mn>
</mroot>
</mrow>
<mrow style="border:1px;">
<mtext mathsize="49">aaa3</mtext>
<mroot style="border:1px" closed="true">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">124567</mn>
</mroot>
</mrow>
<mrow style="border:1px;" dir="rtl">
<mtext mathsize="49">aaa3</mtext>
<mroot style="border:1px" closed="true">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">124567</mn>
</mroot>
</mrow>
<mrow style="border:1px;" dir="rtl">
<mtext mathsize="49">aaa3</mtext>
<mroot style="border:1px" closed="true">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">12</mn>
</mroot>
</mrow>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow style="border:1px;">
<mtext>1</mtext>
<mo>+</mo>
<msqrt>
<mtext>2</mtext>
</msqrt>
</mrow>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow mathsize="100" style="border:1px">
<msup>
<mroot style="border:1px" closed="true">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">12</mn>
</mroot>
<mn style="border:1px">3</mn>
</msup>
<mo>+</mo>
<msup>
<msqrt style="border:1px" closed="true">
<mi style="border:1px">ABC</mi>
</msqrt >
<mn style="border:1px">3</mn>
</msup>
</mrow>
<mspace linebreak="newline" indentalign="center"></mspace>
<mrow mathsize="100" dir="rtl" style="border:1px">
<msup>
<mroot style="border:1px" closed="true">
<mi style="border:1px">ABC</mi>
<mn style="border:1px">12</mn>
</mroot>
<mn style="border:1px">3</mn>
</msup>
<mo>+</mo>
<msup>
<msqrt style="border:1px" closed="true">
<mi style="border:1px">ABC</mi>
</msqrt >
<mn style="border:1px">3</mn>
</msup>
</mrow>
</math>