Find the electric field at the point 20cm above the centre

[Satellite7able]

Homework Statement

Hi guys, I was hoping I could get some help on this question!
The question: "Find the electric field at the point 20 cm above the center of the square made of 4 charged rods of L = 20cm and Q=1mc each.

Homework Equations

I believe E = (KQ)/r^2 is the only equation needed aside from Pythagoreans theorem.

The Attempt at a Solution

So first I found the distances of all four charges from the point 20cm above. If we say that the charge in the upper left corner is Q1 and then name them clockwise from there (so upper right corner is Q2, bottom right corner is Q3 and bottom left corner is Q4), the distance for Q1 and Q2 is sqrt(200) cm from the point and the distance for Q3 and Q4 is sqrt(1000) cm. I then thought to split each charge into its x and y components, and thought the x components of the charges should cancel because it is symmetric? The y components I calculated using the equation above and then I added them up, but I don't think it is the right answer.

Could somebody please lead me in the right direction? Thank you!

 

[kuruman]

You are using the equation for the electric field generated by point charges. The problem specifies that you have charged rods. You need to find an expression for the electric field due to a charged rod at some distance from its midpoint then use superposition.