Question

Racionalize $\frac{5}{2\sqrt{5} }$

Answer 1

Simples, observe:

$\frac{ 2\sqrt{5} }{2 \sqrt{5} } \times \frac{5}{2 \sqrt{5} } = > \frac{10 \sqrt{5} }{4 \times 5} = \frac{ \sqrt{5} }{2}$