Please help with this Physics Lab. I need help with #3, as well as checking my answer for #4, and I need help with #5.Thanks!

Investigating distance apart: Where do you think we should measure distances from, the SURFACE or the CENTER of mass of the object? (Circle) Set the masses of each at 10 Kg. Move the ruler so one center is on Zero (0) meter distance and the other center on 2 meter mark. (you should get a reading very close to 1.67 X 10-9 Newtons) Note: Drag the ruler over the top of both spheres. Move the blue ball to the left side. 1.67 x 10-9 N 1. What is the Gravitational Force on each of the balls? Now double the distance from the centers, move to the 4 meter mark. (4.17 X 10-10 Newtons) 2. What is the Gravitational Force on each of the balls? 4.17 x 10-10 N 3. What is the change in the forces? Divide your first number by the second number. What is the approximate closest whole number? Answer: ??? Now triple the distance from the centers, move to the 6 meter mark. (1.85 X 10-10 Newtons) 4. What is the change in the forces? the forces decrease as the distance triples._ 5. Divide your first number by this third number reading. What is the approximate closest whole number? Answer: ??????