Cropping in Lightroom

I cannot find pre-set cropping such as 6x4 or 8x11 as in Photoshop in Lightroom. How do I crop if I want to print a 6x4 photo?

I have Lightroom 4.3 Beta. I downloaded the final trial version but don't see any differences between Beta and the final versions. Are there any major differences between these the beta and the final product?