Angle
an angle
Angle
a rainbow 
Yes. Any two rays which have the same end point.
angle
An angle.
rainbow
An angle!
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.
A figure formed by two rays with the same endpoint is called an angle. The point where the two rays meet is known as the vertex of the angle, while the rays themselves are referred to as the sides. Angles can be measured in degrees or radians and are classified based on their measures, such as acute, right, obtuse, or straight.
angle
A line