If 5 = 2.236 , then the value of 1 5 is = ?

Answer: Option B

$$\begin{array}{rl}& =\frac{1}{\sqrt{5}}\\ & =\frac{1}{\sqrt{5}}\times \frac{\sqrt{5}}{\sqrt{5}}\\ & =\frac{\sqrt{5}}{5}\\ & =\frac{2.236}{5}\\ & =0.447\end{array}$$