Calculating Dish Resolution at 4 GHz with 3m Diameter - Homework Problem

[wakejosh]

Homework Statement

A dish operates at a frequency of 4 GHz and has a diameter of 3 m. What is its resolution?

Homework Equations

my take home quiz referres me to a page number in my book for the equation, but I have an older book so I can't find it. i think it is the equation for the Limiting angle of resolution of a circular aperture, but I am not sure. something like:
x = 1.22(y GHz/ D) is this what I am looking for?

The Attempt at a Solution

If I try it with this equation I get: 1.63 degrees. any help is appreciated. thanks.

 

[hage567]

x = 1.22(y GHz/ D) is this what I am looking for?

As long as "y GHz" means the wavelength.