Question 936684
The tutor may have wanted you to re-arrange the formula first and then solve(?).
{{{E=I/d^2}}}
{{{d^2=I/E}}}
{{{highlight(d=sqrt(I/E))}}}
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{{{d=sqrt(100/25)}}}
{{{d=sqrt(4)}}}

{{{highlight(d=2)}}}{{{m}}}