**First Law**

“The orbit of every planet is an ellipse with the sun at one of the foci.”

**First Law**

“The orbit of every planet is an ellipse with the sun at one of the foci.”

**Second Law**

“A line joining a planet and the sun sweeps out equal areas during equal intervals of time.”

**Third Law**

“The squares of the orbital periods of planets are directly proportional to the cubes of the semi-major axis of the orbits.”

P = orbital period of planet

a = semimajor axis of orbit

Read about coordinate systems.

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