Well, why not? They were both formed in the same universe, with the same elements, and with matter. I believe they even call Venus "Earth's evil twin sister". It used to share more similarities with Earth than it does now, the greenhouse gases got trapped in it's atmosphere and caused the planet to heat.... And, a lot of other stuff that I don't quite understand well enough to explain here. :p
'Titan' one of Saturn's moons is most like our planet Earth, though it's gravity is very low. It actually has liquid in the same way we have water, but titan's liquid is hydrocarbon (I think..). Earth is roughly the same size as Venus, and we both have the greenhouse effect. Those are the only ways I know that Venus and Earth are similar.
If you mean in what ways are they relates, then have a look here:
http://funadvice.com/r/14q7vssu3el
Both are a similar size, have a similar mass and have the same rocky crust that you could walk on. They are two of the most similar planets to each other in most of their properties.
Cuz they r almost same in size they have found traces of water on the planet Venus a atmosphere its filled with diffrent gases but it is the closet planet to be alike with earth
with the exception that Earth has a magnetic field (deflects cosmic rays) and Venus does not- which is 1 of the reasons we live here and not there...
