The following all show the same star, but each shows a different planet orbiting the star. The diagram are all scaled the same. (For example, you can think of the tick along the line that passes through the Sun and nearest and farthest points in the orbit as representing distance in astronomic al units (AU).) Rank the planets from the left to right based on their average orbital distance from the star, from longest to shortest. (Distance are to scale, but planet and star sizes are not.)

Assuming from left to right (from attached diagram) as A, B, C, D and E, respectively. The longest distance is D, 2nd longest is C, 3rd is E, 4th is B and 5th (shortest) is A.

Explanation:

Question was missing a diagram which I have included. Please refer to the diagram for understanding the answer.

The shapes of the orbit represents a geometry called Ellipse. An Ellipse is a curve made around two focus points (foci) such that the sum of the distances of any point on the curve from these foci is always constant (Diagram included for explanation). An Ellipse has two axes, the major axis (longer in length) and the minor axis (shorter in length). In the given illustration, the line passing through the Sun is the major axis of those Ellipses. Halving that distance can give us the average distance of the sun from the planet.

For simplicity let's call this average distance "R" and the Astronomical units of distance "AU". From the diagram it can be seen that:

For diagram D, R = 10/2 = 5 AU,

For diagram C, R = 7/2 = 3.5 AU,

For diagram E, R = 4/2 = 2 AU,

For diagram B, R = 3/2 = 1.5 AU,

For diagram A, R = 2/2 = 1 AU,