(2)20:3 20/3

(3) 1:4 3: 1

(4)7:5

2,( 1)√ (2)√(3)×(4)×

3，x=0.8 x=4/3 x=5

4. (Write it yourself)

P 67 1。 (1) A: Out of proportion. Because the side length and area of a square are not two related quantities.

A: Yes, in direct proportion. Because their proportion is certain.

A: Yes, it is inversely proportional. Because the number of pages read every day × time = the total number of pages (certain).

(1). (2) It is inversely proportional. (3) Out of proportion.

3。 (1) A: X and Y are directly proportional, and directly proportional.

(2)y=8 x=24