How does the period of revolution of a planet around the sun vary with its distance from the sun?

For planets revolving round the sun, show that T^(2) prop r^(3) , where T is the time period of revolution of the planet and r is its distance from the sun.

According to Kepler, the period of revolution of a planet ( T ) and its mean distance from the sun ( r ) are related by the equation

According to Kepler, the period of revolution of a planet ( T ) and its mean distance from the sun ( r ) are related by the equation

Accorrding to Kepler, the period of revolution of a planet (T) and its mean distance from the Sun ® related by the equation.