How does the law of inertia relate to how the planets in our solar system revolve around the sun?

The law of inertia relates to revolution of planets round the sun due to constant motion of the planets round the sun.

Explanation:

Law of inertia states that a body at rest or uniform motion will continue to be at rest or uniform motion unless it is acted upon by an external force.

The gravitational force keeps the planets revolving round the sun in a uniform motion, this will continue till infinity unless equal and opposite force acts on our planets.

Therefore, the law of inertia relates to revolution of planets round the sun due to constant motion of the planets round the sun.