Which roof type is made primarily of two planes that connect at angles?

The roof type characterized by two planes that connect at angles is the gable roof. Gable roofs feature two sloped sides that meet at a ridge, creating an angled appearance that allows for effective water runoff and adds to the aesthetic appeal of the structure. This design also typically provides additional space for an attic or higher ceilings in rooms.

Hip roofs, the chosen answer, are indeed formed by sloping sides but do not meet at a central ridge like gable roofs; instead, they slope down from all sides of the structure. Flat roofs are, as the name suggests, almost level, while gambrel roofs have a distinctive two-sided slope similar to a barn design. Each of the other roof types mentioned serves a different architectural purpose and has unique characteristics that differentiate them from gable roofs.