SPH4U University Grade 12 Physics - Coulomb's Law?

[burhan101]

Homework Statement

SPH4U University Grade 12 Physics - Coulomb's Law?
I have to determine the answer using Coulomb's Law. Please help me figure out how to do this !

Three point charges, q₁= -5.00 μC, q₂= -4.00 μC, and q₃ which is negative are arranged as shown on three corner of side a=0.500 m. The direction of the forces on qt is at +20.0° with respect to the + x axis.
Calculate the magnitude of q₃

Homework Equations

Coulomb's Law

The Attempt at a Solution

I don't even know how to start

 

[Camille]

Can you attach a picture or describe how q1 and q2 are situated?