I have already asked this in another thread. Here is more explanation:

The radius of earth's orbit is 1.5 * 10^8km & the radius of venus's orbit is 1.1 * 10^8 km.
We need to find out the distance from earth to venus for both positions of venus.

A picture is uploaded here if that helps:

hmmmmm sorry... looks like I can't post a link here. I uploaded an image to photobucket and was trying to post the link here.

I find 3*10^8 km for 30 degrees angle, by solving the equation I posted on the other thread.

Correction, the solutions are:

2.1*10^8 km and 0.49*10^8 km.