Question

A área de um quadrado cuja diagonal mede 2√7,vale:

Answer 1

$Resolu\c{c}\~ao\to \left\{\begin{array}{ccc}d=l \sqrt{2} \\\\2 \sqrt{7} = l \sqrt{2}\\\\l = \frac{2 \sqrt{7} }{ \sqrt{2} }* \frac{ \sqrt{2} }{ \sqrt{2} } = \frac{2 \sqrt{14} }{2}\\\\\boxed{l = \sqrt{14} }\\\\\boxed{\boxed{A = l^2 = ( \sqrt{14} )^2 = 14}} \end{array}\right$

Espero ter ajudado. :))