We have more than thirty excellent geometry lessons here, broken up in general topics. Make sure to browse all of the topics to find what you need, or search by keyword.

Graphing Lines

• Asymptotes
• Domain and Range
• Finding Asymptotes
• Finding Horizontal Asymptotes
• Point Slope Form
• Slope Intercept Form
• Slope of a Line
• X-Y Axis
• Graphing a Parabola

Shapes

• Triangles
• 30-60-90 Right Triangle
• Parallelograms
• Trapezoids
• Special Parallelograms
• Congruent Triangles
• Isosceles Triangles
• Polygons

Angles, Lines, and Points

• Distance Formula
• World of Angles
• Special Angles
• Parallel Lines
• Length of a Line Segment
• Sum of the Angles of a Triangle
• Exterior Angles of a Triangle
• Interior Angles of a Polygon
• Triangle Inequalities
• Midpoint Formula

More Lessons

• Completing the Square In Circle Equations
• Geometric Mean
• Geometric Terms
• Geometry Vocabulary

Formulas

• Area Formulas
• Perimeter Formulas
• Surface Area
• Volume Formulas

Other Stuff

• Important Geometry Vocabulary
• Vertical Angles

Lessons from Other Sites

• Areas, Volumes, Surface Areas
• Circumference of a Circle
• Classifying Angles
• Conic Sections/Circles
• Interior Angles of Regular Polygons
• Polygon Basics
• Pythagorean Theorem
• Three-Dimensional Figures

Recent Geometry Questions

Featured Lesson

Read up on the properties of 30-60-90 right triangles.