Question 1029427
*[illustration semi.JPG].
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From the diagram,
{{{S^2+(2S)^2=R^2}}}
{{{S^2+4S^2=R^2}}}
{{{5S^2=R^2}}}
{{{S^2=R^2/5}}}
The area of a square with side, {{{2S}}}, would be,
{{{A=(2S)^2}}}
{{{A=4S^2}}}
{{{A=(4/5)R^2}}}
{{{A=(4/5)(25)}}}
{{{A=20}}}{{{cm^2}}}