Get into geometry. In geometry, you'll learn about the properties of lines, segments, angles and shapes.[3]You'll memorize a number of theorems and corollaries that will help you to understand the rules of geometry.You'll learn how to calculate the area of a circle, how to use the Pythagorean theorem and how to figure out relationships between angles and sides of special triangles.You'll see a lot of geometry on future standardized tests like the SAT, the ACT and the GRE.