Angular magnification of a microscope

[viperassasin]

Homework Statement

The image formed by a microscope objective with a focal length of 5.00\;{\rm mm} is 160\;{\rm mm} from its second focal point. The eyepiece has a focal length of 26.0\;{\rm mm}. What is the angular magnification of the microscope?

Homework Equations

The Attempt at a Solution

don't know what equation I should use.

 

[mgb_phys]

Look at magnification on wikipedia

 

[viperassasin]

no help

that doesn't help