Understanding high school geometry can be beneficial for upper division math, particularly for topics like trigonometry and proofs. While some students manage to excel in lower division math without a strong geometry background, knowledge of geometric concepts is often crucial for grasping advanced topics. Geometry helps develop proof skills, which are essential in higher mathematics. Familiarity with vectors and matrices, typically covered in geometry courses, is also important for advanced linear algebra and physics. Although some argue that specific geometry results may not be directly applicable in higher math, concepts like similar triangles and parallel lines can occasionally arise. Overall, while geometry may not be strictly necessary, having a foundational understanding can enhance mathematical proficiency and problem-solving skills. If time is limited, focusing on essential topics and seeking resources when needed is advisable.