In a right triangle for an acute angle x, if $$\sin x \frac{3}{7}$$, then find the value of $$\cos x$$.

A

$$\frac{2}{7}$$

B

$$\frac{3}{4}$$

C

$$\frac{1}{\sqrt{3}}$$

D

$$\frac{2\sqrt{(10)}}{7}$$