Cross-sectional area

Cross-sectional area is the area of a two-dimensional slice through a three-dimensional object, measured in a plane perpendicular to a chosen direction or axis.

Plane: A flat, two-dimensional surface extending without limit in three-dimensional space. A cross section lies in a plane through the object.
Cross section (geometry): A plane figure formed by intersecting a three-dimensional solid with a plane. Its area is the geometric quantity measured by a cross-sectional-area calculation.
Area moment of inertia: A geometric measure of how a plane area's material is distributed around an axis. A beam's cross-sectional shape and area distribution determine resistance to bending.
Longitudinal section: A cut or view made along the long axis of an object. It runs along an object's length rather than across it.
Area: A measure of the size of a two-dimensional region, expressed in square units. Cross-sectional area applies this measure to a particular slice.
Disk method: A method for finding a solid's volume by integrating circular cross-sectional areas. It accumulates slices whose areas are determined by their radii.
Current density: Electric current per unit area through a surface perpendicular to current flow. The conductor's cross-sectional area links total current to current density.
Oblique section: A cut through an object made at an angle to its principal axes. Its area can differ from a perpendicular section of the same object.
Intersection: The set of points shared by two or more geometric objects. A cross section is the intersection of an object with a plane.
Washer method: A method for finding volume by integrating areas of washers formed between two radii. Hollow cross sections require subtracting the inner area from the outer area.

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