Question 767524
Actually the answer would be {{{84}}} (not {{{84^2}}})  See below: 

The length of the third triangle side would be solved as follows:
	{{{a^2 + b^2 = c^2}}}, ie.
	{{{4^2 + b^2 = 10^2}}}
	{{{16 + b^2 = 100}}}
	{{{b^2 = 100 - 16}}}
	{{{b = sqrt(84)}}} which will be slightly larger than 9

This makes sense, because 10, as the hypotenuse, would be the longest side.

Therefore, one side of the square would be {{{sqrt(84)}}}.

Now, the area of the square would be computed as follows:
	{{{a = s^2}}}
	{{{a = (sqrt(84)) * (sqrt(84))}}}
	{{{a = 84}}}