Electric field strength of a wire comparison

[pickleparty]

1. Homework Statement

The electric field strength 7.79 cm from a very long charged wire is 2660 N/C. What is the electric field strength (in N/C) 12.7 cm from the wire?

2. Homework Equations

E= (9*10^9) Q/ r^2

3. The Attempt at a Solution

i have energy. so is tried to solve backwards for the first one for Q. Then i plugged in the new Q with relation to 0.127 m. I got 1001 N/C which is wrong. Am I even using the right formula?

 

[Gear300]

Do you know Gauss's Law?

 

[pickleparty]

ya is that what i needed to use?