To find the reflected coordinates of point A (3, 5) across the x-axis, we change the sign of the y-coordinate.
The reflection of point A (3, 5) across the x-axis is (3, -5).
Now we can calculate the distance between the original point A (3, 5) and the reflected point A (3, -5). The distance between two points \((x_1, y_1)\) and \((x_2, y_2)\) in the coordinate plane can be found using the distance formula:
\[ d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} \]
Substituting the coordinates of the two points:
\[ d = \sqrt{(3 - 3)^2 + (-5 - 5)^2} = \sqrt{0^2 + (-10)^2} = \sqrt{100} = 10 \]
Therefore, the distance between the original point A and the reflected point A is 10.