Edge in Geometry

In geometry, an edge refers to the line segment where two faces of a solid figure meet. It is the intersection of two faces, and it is one-dimensional, meaning it has length but no width or height.

Identifying Edges

To identify edges in a solid figure, look for the line segments where the faces meet. For example, in a cube, each of the 12 line segments where the faces meet is an edge.

Counting Edges

The number of edges in a solid figure can be determined by adding the number of edges each face contributes. For example, a cube has 6 faces, and each face contributes 4 edges, so the total number of edges is 6 * 4 = 24.

Study Guide

• Understand that an edge is a line segment where two faces of a solid figure meet.
• Practice identifying edges in different solid figures, such as cubes, rectangular prisms, and pyramids.
• Learn to count the number of edges in various solid figures by adding the number of edges contributed by each face.