In the equation for gravitational force between two objects, the quantity that must be squared is the distance between the centers of the two objects.

Here's the equation:

F = G * (m1 * m2) / r²

Where:

* F is the force of gravity

* G is the gravitational constant

* m1 and m2 are the masses of the two objects

* r is the distance between the centers of the two objects

The inverse square law dictates that the force of gravity decreases proportionally to the square of the distance between the objects. So, if you double the distance, the force of gravity becomes four times weaker.