A line in geometry is a straight path that goes on forever in both directions. It has no thickness and is usually drawn between two points, but it keeps going without stopping. Lines are important for making shapes, measuring distances, and understanding angles. For example, the edge of a ruler can represent a line.
Foundations
Learn the basic concepts of lines, points, planes, angles, slopes, and their applications in coordinate geometry.
- Introduction to Lines
- Types of Lines
- Line Segment
- Points, Lines and Planes
- Collinear Points
- Lines and Angles
- Horizontal Line
- Vertical Line
- Real-World Applications of Slope-Intercept Form
Slope of a Line
Learn how to calculate and interpret the slope of a line, including slope formulas, intercepts, zero slope, and related practice problems.
Forms of Equation of a Straight Line
Understand different forms of straight-line equations and how to write, graph, and analyze them.
- Equation of a Straight Line
- How to Find the Equation of a Straight Line
- Point-Slope Form
- Slope-Intercept Form
- Writing Slope-Intercept Equations
- Graphing Slope-Intercept Equations
- Standard Form of a Straight Line
- Family of Lines
- Equation of a Line in 3D — Cartesian and Vector Form
Types & Relationships Between Lines
Explore parallel, perpendicular, intersecting, concurrent, transversal, and skew lines along with their properties and relationships.
- Parallel Lines
- Properties of Parallel Lines
- Lines Parallel to the Same Line
- Parallel and Perpendicular Lines
- Parallel vs Perpendicular vs Transverse Lines
- Intersecting Lines
- Concurrent Lines
- Transversal Lines
- Skew Lines
- Perpendicular Bisector
- Construction of Perpendicular Lines
Distance & Angle Between Lines
Study how to calculate distances and angles between lines in 2D and 3D geometry.