What is the name of the rafter that makes a 90-degree intersection with both the top plate and ridge board?

The term for the rafter that creates a 90-degree angle intersection with both the top plate and the ridge board is known as a common rafter. Common rafters are typically used in conventional roof framing, forming the basic structure of the roof by extending from the ridge down to the top plate of the wall. They are vital in providing the sloped surface needed for roofing materials to shed water effectively.

In contrast, a hip rafter serves to support the ends of a hip roof and is typically angled to form a connection between the ridge board and the outer edges of the roof. Valley rafters, on the other hand, are used in situations where two roof slopes intersect to form a valley. Jack rafters are shorter rafters that support the roof sections between the hip or valley rafters and the wall plates. These definitions clarify the unique roles of each rafter type and illustrate why the common rafter is the most fitting choice for this particular question.