Which term describes a spherical triangle forming the transition from the circular plan of a dome to the polygonal plan of its supporting structure?

Which term describes a spherical triangle forming the transition from the circular plan of a dome to the polygonal plan of its supporting structure?

• A. Pendentive
• B. Narthex
• C. Nave
• D. Stylobate

Answer: (A)

The situation is about how a dome's weight is carried down to the walls when the dome sits on a base that isn’t circular. Pendentives are the curved, triangular surfaces that connect the circular dome to the square (or polygonal) supporting structure. These spherical triangles slope upward from the corners of the square to meet the dome, creating a smooth transition from a circular plan to a polygonal plan. This mechanism lets a dome crown a square or multi-angled room and distributes the load efficiently into the supporting walls or piers. Narthex, nave, and stylobate refer to other architectural features: an entrance vestibule, the main interior space of a church, and the platform that supports a classical colonnade, respectively—none of these describe the load-transfer transition from a dome to a polygonal base.

The situation is about how a dome's weight is carried down to the walls when the dome sits on a base that isn’t circular. Pendentives are the curved, triangular surfaces that connect the circular dome to the square (or polygonal) supporting structure. These spherical triangles slope upward from the corners of the square to meet the dome, creating a smooth transition from a circular plan to a polygonal plan. This mechanism lets a dome crown a square or multi-angled room and distributes the load efficiently into the supporting walls or piers. Narthex, nave, and stylobate refer to other architectural features: an entrance vestibule, the main interior space of a church, and the platform that supports a classical colonnade, respectively—none of these describe the load-transfer transition from a dome to a polygonal base.