How do I compute electric flux through a half-cylinder

[micro435]

Homework Statement

In figure 1, take the half-cylinder's radius and length to be 3.4cm and 15cm respectively.

If the electric field has magnitude 5.9 kN/C, find the flux through the half-cylinder. Hint: You don't need to do an integral! Why not?

Homework Equations

The Attempt at a Solution

I tried finding the area of the cylindrical surface and multiplying that by the magnitude of the electric field. That didn't work. Then I tried finding the area of the rectangle that would be the further side of the half-cylinder and multiplying that by the electric field but again, that didn't work.

Do I need to use a different equation? I was originally using flux = E * A. Should I be using something else?

 

[gneill]

Can you show the details of your calculation for the rectangular area method? E*A should work. Are you supposed to specify the result in particular units?