Geometry Help and Problems
This section is all about key geometric concepts, theorems, and proofs. Learn how to write mathematical arguments in the form of a two-column geometric proof and study the different properties of shapes by working through these insightful lessons.
Just starting out in geometry? This group of lessons will introduce you to the mathematical study
of shapes. Geometry is one of the oldest branches of mathematics, with a rich history and many
different real world applications. Read on to learn the geometry basics you should know as a
Lines and angles are some of the most important topics in geometry. These lessons will teach
you about their different properties, as well as the different categories of lines and angles you’ll
need to be familiar with as a geometry student. Our section on lines and angles ends with an
introduction to postulates and theorems.
Do you know the difference between equilateral and equiangular triangles? Can you prove
the congruence of two triangles? The study of these three-sided shapes is the first step after
learning about lines and angles, and will provide an essential foundation for future topics in
Quadrilaterals are the next topic for advancing geometry students. Unlike triangles, these four-
sided polygons come in many different shapes: squares, rectangles, trapezoids, and more.
In these lessons, you will learn the properties of different quadrilaterals and expand your
knowledge of geometry.
Once you’ve become familiar with different shapes, you can start to examine them in more
complicated ways. These lessons describe how to calculate the areas of polygons and circles.
We also include helpful reference tables you can use for homework or test review.