It is appropriate--that is, correct--to define or describe a subtended angle as an angle whose vertex begins at the center of a circle or sphere, and passes through the endpoints of the arc of the particular circle/sphere?
It is appropriate--that is, correct--to define or describe a subtended angle as an angle whose vertex begins at the center of a circle or sphere, and passes through the endpoints of the arc of the particular circle/sphere?
You should be more specific, in general a subtended angle is from a point and is the angle between the extremities of the "thing" at the point.