Key Concepts: Representations of Three-Dimensional Figures

Cross Sections

A cross section is the intersection of a solid and a plane. The shape depends on the solid and the angle of the plane.

Examples

• A plane parallel to the base of a cylinder creates a circle.
• A plane through the apex of a cone creates a triangle.
• A plane at an angle through a cylinder creates an ellipse.

Nets

A net is a two-dimensional pattern that folds to form a three-dimensional figure. Nets are useful for visualizing and calculating surface area.

Orthographic and Isometric Views

• Top view, front view, and side view are orthographic projections.
• Isometric view shows three faces of a solid in one drawing.