Rotational bodies

A rotational body (or solid of revolution) is a three-dimensional object formed by rotating a two-dimensional figure about a fixed axis. The most common rotational bodies are the cylinder, cone, and sphere, each generated by rotating a specific plane figure (rectangle, right triangle, semicircle) about an axis.

Important properties

• The axis of rotation is the line about which the figure is rotated.

• The cross-sections perpendicular to the axis are often circles.

• The volume and surface area of rotational bodies can be calculated using geometric formulas.

• Rotational symmetry: these bodies look the same after rotation around their axis.