What is the distance to the earth’s horizon from point P?

Enter your answer as a decimal in the box. Round only your final answer to the nearest tenth.
x = mi
A circle representing earth is shown. The center of the circle is labeled earth's center. From the center, a radius labeled 3959 miles goes up and to the right until it touches the circle. This radius extends outside the circle to point P. The segment on the circle out to point P is labeled 5.9 miles. A line segment is shown that goes from point P vertically downward until it stops at the farthest right point on the circle and is labeled x. From the farthest right point of the circle, a line segment is drawn horizontally to the center of the circle and is labeled 3959 miles.