At a distance of 1 a. u., the earth takes one year to travel around the sun. how far away is a planet that takes eight years to go around the sun?

4 AU

Explanation:

We can solve the problem by using Kepler's third law, which states that the ratio between the square of the period of revolution of a planet around the Sun and the cube of its average distance from the Sun is constant for every planet orbiting the Sun:

where

T is the orbital period

r is the average distance of the planet from the Sun

If we take two planets 1 and 2, the equation can be rewritten as

In this problem, we have:

is the orbital period of the Earth

is the distance of the Earth from the Sun

is the orbital period of the second planet

Therefore, we can re-arrange the equation to calculate r2, the averag distance of the other planet from the Sun:

4

Explanation:

0.55x745.7j and a calculator