In geometry, defined terms are basic terms that are explained using other known words. These terms are the building blocks of geometric concepts and are essential for understanding more complex ideas. Some common defined terms in geometry include point, line, and plane.
1. **Point**: A point is a location in space that has no size or dimension. It is represented by a dot and is usually named with a capital letter.
2. **Line**: A line is a straight path that extends infinitely in both directions. It has no thickness and is made up of an infinite number of points. A line is typically named by two points on the line or by a lowercase letter.
3. **Plane**: A plane is a flat, two-dimensional surface that extends infinitely in all directions. It has no thickness and is made up of an infinite number of lines. A plane is usually named by three points on the plane or by a capital letter.
These defined terms help us describe and understand the properties and relationships of geometric figures. By using these basic terms, we can build more complex definitions and theorems in geometry.