Balls exerting gravitational force on eachother

[Axl Rose]

Homework Statement

Two balls, each with a mass of 0.790 kg, exert a gravitational force of 8.39 x 10^-11 N on each other. How far apart are the balls? The value of the universal gravitational constant is 6.673 x 10^-11 N m^2/kg^2. Answer in units of m.

Homework Equations

F = (G * m1 * m2) / r²

The Attempt at a Solution

8.39 * 10^-11 = (6.673 * 10^-11 * 0.79 * 0.79) / r²
r² = 2.0145899
r = 1.42m

The physics program that I am using says 1.42 m is incorrect. I have checked my work, but I still get 1.42 m. Help?

edit: Sorry, I messed up the topic title :(

 

[hage567]

r² = 2.0145899

This isn't quite right. You haven't isolated r² properly. What you have here is really 1/r². You need to flip it so you are solving for r².