The appreciation of the direction of the cue ball after the stroke is not easy.

It's because the angle formed initially by the 3 balls on the table is not the real direction angle.

TO PREVIEW THE DIRECTION OF MY BALL

Before taking its final direction, the cue ball always stops a ball before the played ball.

The angle of direction to be appreciated is the one formed by the cue ball in contact with the played ball and the third ball.
This 4nd ball is called 'the ghost ball'.

TRICK :

To appreciate the real angle of the direction all you have to do is to imagine a 4th virtual ball which would be the cue ball knocking the played ball

Thus, you can visualize the real angle of direction.

The angle is larger in degrees ( we say obtuser ) than the angle formed by the 3 balls on the table.

I see a rigth angle ?

It is an obtuse angle.

I see an acute angle ?

It is a right angle !

APPRECIATING DIRECTIONS

The real angle of direction to be appreciated for the bounces is the one formed by the direction taken by the cue ball and the cushion.

Note that when touching the cushion the center of the cue ball is at a radius distance from the cushion itself.

It is this to be taken in reference to appreciate the bounce of the cue ball

TRICK :

To have a good vision of the bounces, all you have to do is to draw a line ( with a chalk pen ) along the cushion, at a radius distance from it.

For every bounce, we can now estimate a point of this line corresponding at the center of the cue ball touching the cushion.

From this point, if we draw a perpendicular, we can now visualize :

- the angle of incidence

- finally the angle or reflection, that is the real way of the cue ball

Incidence and reflection angles are identical on each side of the perpendicular at the cushion on the touching point