One
They have one point in common.
One
maybe
No, they only have the one common endpoint in common.
opposite rays have common end points
An angle
The meeting points of two rays is called a vertex
It is 360 degrees.
if the rays have no common points, the answer is zero. if the rays all have the same end point, the answer is 21 -- counting only the acute angles.
One
An angle is the intersection of two rays with a common endpoint. Adjacent Angles are 2 angles that share a common vertex, a common side and no common interior points.
An angle separates a plane to 3 sets: 1) Points between the 2 rays 2) Points on one of the rays 3) Points outside of the 2 rays