Answer :
they help the divide the world and describe the difference in weather patterns
The tropic of cancer and tropic of capricorn has inportance in geographical studies. They help to divide the oceans. They help to classify different countries ( as lying in and around of either of the zones). On classifying, we can also predict weather or atmospheric pressure over the country ( with respect to tropic of cancer or tropic of capricorn). Thus, it has important role in geography.