Question 873945
{{{A=(1/2)bh}}}
{{{A=(1/2)b(2b)}}}
{{{A=b^2}}}
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.
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{{{b^2+h^2=10^2}}}
{{{b^2+(2b)^2=10^2}}}
{{{b^2+4b^2=100}}}
{{{5b^2=100}}}
{{{b^2=20}}}
So,
{{{A=20}}}