(1) This is a fan-shaped statistical chart. As can be seen from the statistical chart, there are the most supplementary books.

(2) The number of story books is: 45,000× 20% = 9,000 (copies),

The number of sci-tech books is: 45,000× 25% =11250 (volume).

The number of learning tools is: 45000×40% = 18000 (copies);

(3)( 18000- 1 1250)÷ 1 1250× 100%

=6750÷ 1 1250× 100%,

=0.6× 100%,

=60%;

(4) The number of cartoons is: 45,000×15% = 6,750 (copies),

The ratio of teaching materials to cartoons is:18000: 6750 = 8: 3;

So the answers are: (1) fan, learning AIDS, (2)9000, 1 1250, 18000, (3)60, (4) 8: 3.